"An attempt to connect to failed...."

This seems to be the reoccurring error:

9:44:00 AM [email protected] [SMTP]  MailExceptions.ConnectionException: Connection failed due to the following reason: 

9:44:00 AM     “The handshake failed due to an unexpected packet format.” —> System.IO.IOException: The handshake failed due to an unexpected packet format.

Hello nobrien,
please try making exceptions in Windows firewall and your Anti-virus software for eM client and see if the issue persists.
Otherwise, please copy the whole error from Tools>Operations>Log when it appears, as you only included the first line here. You can use the Ctrl+A shortcut to select all lines in the log and then copy it out.

Regards,
Olivia

Here you go:
2:21:18 AM    at MailClient.Smtp.SmtpSendCommand.Execute(WorkerStatus status)2:21:18 AM    at MailClient.Commands.Command.Process(WorkerStatus status)
2:21:18 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/
2:21:18 AM [email protected] [GData]  Synchronizing folder list
2:21:18 AM [email protected] [IMAP]  Synchronizing subfolders: Done
2:21:18 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/Inbox
2:21:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
2:21:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/Dr. Fox
2:21:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
2:21:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/Mom and Dad
2:21:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
2:21:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/Product Info
2:21:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
2:21:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/USNA
2:21:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
2:21:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/[Gmail]
2:21:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
2:21:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/Mom and Dad/Taxes
2:21:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
2:21:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/[Gmail]/Trash
2:21:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
2:21:27 AM [email protected] [GData]  Synchronizing folder list
2:21:28 AM [email protected] [GData]  Synchronizing folder list
2:21:28 AM [email protected] [GData]  Synchronizing folder ‘[email protected]/Contacts/’
2:21:28 AM [email protected] [GData]  Synchronizing folder ‘[email protected]/[email protected]/’
2:30:56 AM [email protected] [SMTP]  Connecting: To [email protected]
2:31:18 AM [email protected] [SMTP]  MailExceptions.ConnectionException: Connection failed due to the following reason: 
2:31:18 AM     “The handshake failed due to an unexpected packet format.” —> System.IO.IOException: The handshake failed due to an unexpected packet format.
2:31:18 AM    at System.Net.Security.SslState.StartReadFrame(Byte[] buffer, Int32 readBytes, AsyncProtocolRequest asyncRequest)
2:31:18 AM    at System.Net.Security.SslState.StartReceiveBlob(Byte[] buffer, AsyncProtocolRequest asyncRequest)
2:31:18 AM    at System.Net.Security.SslState.CheckCompletionBeforeNextReceive(ProtocolToken message, AsyncProtocolRequest asyncRequest)
2:31:18 AM    at System.Net.Security.SslState.StartSendBlob(Byte[] incoming, Int32 count, AsyncProtocolRequest asyncRequest)
2:31:18 AM    at System.Net.Security.SslState.ForceAuthentication(Boolean receiveFirst, Byte[] buffer, AsyncProtocolRequest asyncRequest)
2:31:18 AM    at System.Net.Security.SslState.ProcessAuthentication(LazyAsyncResult lazyResult)
2:31:18 AM    at System.Net.Security.SslStream.AuthenticateAsClient(String targetHost, X509CertificateCollection clientCertificates, SslProtocols enabledSslProtocols, Boolean checkCertificateRevocation)
2:31:18 AM    at MailClient.Smtp.SmtpSendCommand.Connect(WorkerStatus status)
2:31:18 AM    — End of inner exception stack trace —
2:31:18 AM    at MailClient.Smtp.SmtpSendCommand.Connect(WorkerStatus status)
2:31:18 AM    at MailClient.Smtp.SmtpSendCommand.Execute(WorkerStatus status)
2:31:18 AM    at MailClient.Commands.Command.Process(WorkerStatus status)
2:31:18 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/
2:31:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
2:31:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/Inbox
2:31:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
2:31:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/Dr. Fox
2:31:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
2:31:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/Mom and Dad
2:31:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
2:31:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/Product Info
2:31:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
2:31:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/USNA
2:31:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
2:31:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/[Gmail]
2:31:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
2:31:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/Mom and Dad/Taxes
2:31:20 AM [email protected] [IMAP]  Synchronizing subfolders: Done
2:31:20 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/[Gmail]/Trash
2:31:20 AM [email protected] [IMAP]  Synchronizing subfolders: Done
2:31:28 AM [email protected] [GData]  Synchronizing folder list
2:31:28 AM [email protected] [GData]  Synchronizing folder list
2:31:28 AM [email protected] [GData]  Synchronizing folder ‘[email protected]/Contacts/’
2:40:56 AM [email protected] [SMTP]  Connecting: To [email protected]
2:41:18 AM [email protected] [SMTP]  MailExceptions.ConnectionException: Connection failed due to the following reason: 
2:41:18 AM     “The handshake failed due to an unexpected packet format.” —> System.IO.IOException: The handshake failed due to an unexpected packet format.
2:41:18 AM    at System.Net.Security.SslState.StartReadFrame(Byte[] buffer, Int32 readBytes, AsyncProtocolRequest asyncRequest)
2:41:18 AM    at System.Net.Security.SslState.StartReceiveBlob(Byte[] buffer, AsyncProtocolRequest asyncRequest)
2:41:18 AM    at System.Net.Security.SslState.CheckCompletionBeforeNextReceive(ProtocolToken message, AsyncProtocolRequest asyncRequest)
2:41:18 AM    at System.Net.Security.SslState.StartSendBlob(Byte[] incoming, Int32 count, AsyncProtocolRequest asyncRequest)
2:41:18 AM    at System.Net.Security.SslState.ForceAuthentication(Boolean receiveFirst, Byte[] buffer, AsyncProtocolRequest asyncRequest)
2:41:18 AM    at System.Net.Security.SslState.ProcessAuthentication(LazyAsyncResult lazyResult)
2:41:18 AM    at System.Net.Security.SslStream.AuthenticateAsClient(String targetHost, X509CertificateCollection clientCertificates, SslProtocols enabledSslProtocols, Boolean checkCertificateRevocation)
2:41:18 AM    at MailClient.Smtp.SmtpSendCommand.Connect(WorkerStatus status)
2:41:18 AM    — End of inner exception stack trace —
2:41:18 AM    at MailClient.Smtp.SmtpSendCommand.Connect(WorkerStatus status)
2:41:18 AM    at MailClient.Smtp.SmtpSendCommand.Execute(WorkerStatus status)
2:41:18 AM    at MailClient.Commands.Command.Process(WorkerStatus status)
2:41:18 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/
2:41:18 AM [email protected] [GData]  Synchronizing folder list
2:41:18 AM [email protected] [IMAP]  Synchronizing subfolders: Done
2:41:18 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/Inbox
2:41:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
2:41:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/Dr. Fox
2:41:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
2:41:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/Mom and Dad
2:41:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
2:41:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/Product Info
2:41:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
2:41:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/USNA
2:41:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
2:41:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/[Gmail]
2:41:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
2:41:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/Mom and Dad/Taxes
2:41:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
2:41:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/[Gmail]/Trash
2:41:20 AM [email protected] [IMAP]  Synchronizing subfolders: Done
2:41:39 AM [email protected] [GData]  Synchronizing folder list
2:41:49 AM [email protected] [GData]  Synchronizing folder list
2:41:49 AM [email protected] [GData]  Synchronizing folder ‘[email protected]/Contacts/’
2:41:49 AM [email protected] [GData]  Synchronizing folder ‘[email protected]/[email protected]/’
2:50:56 AM [email protected] [SMTP]  Connecting: To [email protected]
2:51:18 AM [email protected] [SMTP]  MailExceptions.ConnectionException: Connection failed due to the following reason: 
2:51:18 AM     “The handshake failed due to an unexpected packet format.” —> System.IO.IOException: The handshake failed due to an unexpected packet format.
2:51:18 AM    at System.Net.Security.SslState.StartReadFrame(Byte[] buffer, Int32 readBytes, AsyncProtocolRequest asyncRequest)
2:51:18 AM    at System.Net.Security.SslState.StartReceiveBlob(Byte[] buffer, AsyncProtocolRequest asyncRequest)
2:51:18 AM    at System.Net.Security.SslState.CheckCompletionBeforeNextReceive(ProtocolToken message, AsyncProtocolRequest asyncRequest)
2:51:18 AM    at System.Net.Security.SslState.StartSendBlob(Byte[] incoming, Int32 count, AsyncProtocolRequest asyncRequest)
2:51:18 AM    at System.Net.Security.SslState.ForceAuthentication(Boolean receiveFirst, Byte[] buffer, AsyncProtocolRequest asyncRequest)
2:51:18 AM    at System.Net.Security.SslState.ProcessAuthentication(LazyAsyncResult lazyResult)
2:51:18 AM    at System.Net.Security.SslStream.AuthenticateAsClient(String targetHost, X509CertificateCollection clientCertificates, SslProtocols enabledSslProtocols, Boolean checkCertificateRevocation)
2:51:18 AM    at MailClient.Smtp.SmtpSendCommand.Connect(WorkerStatus status)
2:51:18 AM    — End of inner exception stack trace —
2:51:18 AM    at MailClient.Smtp.SmtpSendCommand.Connect(WorkerStatus status)
2:51:18 AM    at MailClient.Smtp.SmtpSendCommand.Execute(WorkerStatus status)
2:51:18 AM    at MailClient.Commands.Command.Process(WorkerStatus status)
2:51:18 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/
2:51:18 AM [email protected] [GData]  Synchronizing folder list
2:51:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
2:51:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/Inbox
2:51:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
2:51:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/Dr. Fox
2:51:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
2:51:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/Mom and Dad
2:51:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
2:51:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/Product Info
2:51:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
2:51:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/USNA
2:51:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
2:51:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/[Gmail]
2:51:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
2:51:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/Mom and Dad/Taxes
2:51:20 AM [email protected] [IMAP]  Synchronizing subfolders: Done
2:51:20 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/[Gmail]/Trash
2:51:20 AM [email protected] [IMAP]  Synchronizing subfolders: Done
2:51:39 AM [email protected] [GData]  Synchronizing folder list
2:51:49 AM [email protected] [GData]  Synchronizing folder ‘[email protected]/Contacts/’
3:00:56 AM [email protected] [SMTP]  Connecting: To [email protected]
3:01:19 AM [email protected] [SMTP]  MailExceptions.ConnectionException: Connection failed due to the following reason: 
3:01:19 AM     “The handshake failed due to an unexpected packet format.” —> System.IO.IOException: The handshake failed due to an unexpected packet format.
3:01:19 AM    at System.Net.Security.SslState.StartReadFrame(Byte[] buffer, Int32 readBytes, AsyncProtocolRequest asyncRequest)
3:01:19 AM    at System.Net.Security.SslState.StartReceiveBlob(Byte[] buffer, AsyncProtocolRequest asyncRequest)
3:01:19 AM    at System.Net.Security.SslState.CheckCompletionBeforeNextReceive(ProtocolToken message, AsyncProtocolRequest asyncRequest)
3:01:19 AM    at System.Net.Security.SslState.StartSendBlob(Byte[] incoming, Int32 count, AsyncProtocolRequest asyncRequest)
3:01:19 AM    at System.Net.Security.SslState.ForceAuthentication(Boolean receiveFirst, Byte[] buffer, AsyncProtocolRequest asyncRequest)
3:01:19 AM    at System.Net.Security.SslState.ProcessAuthentication(LazyAsyncResult lazyResult)
3:01:19 AM    at System.Net.Security.SslStream.AuthenticateAsClient(String targetHost, X509CertificateCollection clientCertificates, SslProtocols enabledSslProtocols, Boolean checkCertificateRevocation)
3:01:19 AM    at MailClient.Smtp.SmtpSendCommand.Connect(WorkerStatus status)
3:01:19 AM    — End of inner exception stack trace —
3:01:19 AM    at MailClient.Smtp.SmtpSendCommand.Connect(WorkerStatus status)
3:01:19 AM    at MailClient.Smtp.SmtpSendCommand.Execute(WorkerStatus status)
3:01:19 AM    at MailClient.Commands.Command.Process(WorkerStatus status)
3:01:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/
3:01:19 AM [email protected] [GData]  Synchronizing folder list
3:01:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
3:01:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/Inbox
3:01:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
3:01:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/Dr. Fox
3:01:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
3:01:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/Mom and Dad
3:01:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
3:01:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/Product Info
3:01:20 AM [email protected] [IMAP]  Synchronizing subfolders: Done
3:01:20 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/USNA
3:01:20 AM [email protected] [IMAP]  Synchronizing subfolders: Done
3:01:20 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/[Gmail]
3:01:20 AM [email protected] [IMAP]  Synchronizing subfolders: Done
3:01:20 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/Mom and Dad/Taxes
3:01:20 AM [email protected] [IMAP]  Synchronizing subfolders: Done
3:01:20 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/[Gmail]/Trash
3:01:20 AM [email protected] [IMAP]  Synchronizing subfolders: Done
3:01:28 AM [email protected] [GData]  Synchronizing folder list
3:01:28 AM [email protected] [GData]  Synchronizing folder list
3:01:29 AM [email protected] [GData]  Synchronizing folder ‘[email protected]/Contacts/’
3:01:29 AM [email protected] [GData]  Synchronizing folder ‘[email protected]/[email protected]/’
3:10:56 AM [email protected] [SMTP]  Connecting: To [email protected]
3:11:18 AM [email protected] [SMTP]  MailExceptions.ConnectionException: Connection failed due to the following reason: 
3:11:18 AM     “The handshake failed due to an unexpected packet format.” —> System.IO.IOException: The handshake failed due to an unexpected packet format.
3:11:18 AM    at System.Net.Security.SslState.StartReadFrame(Byte[] buffer, Int32 readBytes, AsyncProtocolRequest asyncRequest)
3:11:18 AM    at System.Net.Security.SslState.StartReceiveBlob(Byte[] buffer, AsyncProtocolRequest asyncRequest)
3:11:18 AM    at System.Net.Security.SslState.CheckCompletionBeforeNextReceive(ProtocolToken message, AsyncProtocolRequest asyncRequest)
3:11:18 AM    at System.Net.Security.SslState.StartSendBlob(Byte[] incoming, Int32 count, AsyncProtocolRequest asyncRequest)
3:11:18 AM    at System.Net.Security.SslState.ForceAuthentication(Boolean receiveFirst, Byte[] buffer, AsyncProtocolRequest asyncRequest)
3:11:18 AM    at System.Net.Security.SslState.ProcessAuthentication(LazyAsyncResult lazyResult)
3:11:18 AM    at System.Net.Security.SslStream.AuthenticateAsClient(String targetHost, X509CertificateCollection clientCertificates, SslProtocols enabledSslProtocols, Boolean checkCertificateRevocation)
3:11:18 AM    at MailClient.Smtp.SmtpSendCommand.Connect(WorkerStatus status)
3:11:18 AM    — End of inner exception stack trace —
3:11:18 AM    at MailClient.Smtp.SmtpSendCommand.Connect(WorkerStatus status)
3:11:18 AM    at MailClient.Smtp.SmtpSendCommand.Execute(WorkerStatus status)
3:11:18 AM    at MailClient.Commands.Command.Process(WorkerStatus status)
3:11:18 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/
3:11:18 AM [email protected] [GData]  Synchronizing folder list
3:11:18 AM [email protected] [IMAP]  Synchronizing subfolders: Done
3:11:18 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/Inbox
3:11:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
3:11:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/Dr. Fox
3:11:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
3:11:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/Mom and Dad
3:11:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
3:11:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/Product Info
3:11:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
3:11:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/USNA
3:11:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
3:11:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/[Gmail]
3:11:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
3:11:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/Mom and Dad/Taxes
3:11:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
3:11:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/[Gmail]/Trash
3:11:20 AM [email protected] [IMAP]  Synchronizing subfolders: Done
3:11:27 AM [email protected] [GData]  Synchronizing folder list
3:11:28 AM [email protected] [GData]  Synchronizing folder ‘[email protected]/Contacts/’
3:20:56 AM [email protected] [SMTP]  Connecting: To [email protected]
3:21:18 AM [email protected] [SMTP]  MailExceptions.ConnectionException: Connection failed due to the following reason: 
3:21:18 AM     “The handshake failed due to an unexpected packet format.” —> System.IO.IOException: The handshake failed due to an unexpected packet format.
3:21:18 AM    at System.Net.Security.SslState.StartReadFrame(Byte[] buffer, Int32 readBytes, AsyncProtocolRequest asyncRequest)
3:21:18 AM    at System.Net.Security.SslState.StartReceiveBlob(Byte[] buffer, AsyncProtocolRequest asyncRequest)
3:21:18 AM    at System.Net.Security.SslState.CheckCompletionBeforeNextReceive(ProtocolToken message, AsyncProtocolRequest asyncRequest)
3:21:18 AM    at System.Net.Security.SslState.StartSendBlob(Byte[] incoming, Int32 count, AsyncProtocolRequest asyncRequest)
3:21:18 AM    at System.Net.Security.SslState.ForceAuthentication(Boolean receiveFirst, Byte[] buffer, AsyncProtocolRequest asyncRequest)
3:21:18 AM    at System.Net.Security.SslState.ProcessAuthentication(LazyAsyncResult lazyResult)
3:21:18 AM    at System.Net.Security.SslStream.AuthenticateAsClient(String targetHost, X509CertificateCollection clientCertificates, SslProtocols enabledSslProtocols, Boolean checkCertificateRevocation)
3:21:18 AM    at MailClient.Smtp.SmtpSendCommand.Connect(WorkerStatus status)
3:21:18 AM    — End of inner exception stack trace —
3:21:18 AM    at MailClient.Smtp.SmtpSendCommand.Connect(WorkerStatus status)
3:21:18 AM    at MailClient.Smtp.SmtpSendCommand.Execute(WorkerStatus status)
3:21:18 AM    at MailClient.Commands.Command.Process(WorkerStatus status)
3:21:18 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/
3:21:18 AM [email protected] [GData]  Synchronizing folder list
3:21:18 AM [email protected] [IMAP]  Synchronizing subfolders: Done
3:21:18 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/Inbox
3:21:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
3:21:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/Dr. Fox
3:21:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
3:21:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/Mom and Dad
3:21:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
3:21:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/Product Info
3:21:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
3:21:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/USNA
3:21:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
3:21:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/[Gmail]
3:21:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
3:21:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/Mom and Dad/Taxes
3:21:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
3:21:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/[Gmail]/Trash
3:21:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
3:21:39 AM [email protected] [GData]  Synchronizing folder list
3:21:49 AM [email protected] [GData]  Synchronizing folder list
3:21:50 AM [email protected] [GData]  Synchronizing folder ‘[email protected]/Contacts/’
3:21:50 AM [email protected] [GData]  Synchronizing folder ‘[email protected]/[email protected]/’
3:30:56 AM [email protected] [SMTP]  Connecting: To [email protected]
3:31:18 AM [email protected] [SMTP]  MailExceptions.ConnectionException: Connection failed due to the following reason: 
3:31:18 AM     “The handshake failed due to an unexpected packet format.” —> System.IO.IOException: The handshake failed due to an unexpected packet format.
3:31:18 AM    at System.Net.Security.SslState.StartReadFrame(Byte[] buffer, Int32 readBytes, AsyncProtocolRequest asyncRequest)
3:31:18 AM    at System.Net.Security.SslState.StartReceiveBlob(Byte[] buffer, AsyncProtocolRequest asyncRequest)
3:31:18 AM    at System.Net.Security.SslState.CheckCompletionBeforeNextReceive(ProtocolToken message, AsyncProtocolRequest asyncRequest)
3:31:18 AM    at System.Net.Security.SslState.StartSendBlob(Byte[] incoming, Int32 count, AsyncProtocolRequest asyncRequest)
3:31:18 AM    at System.Net.Security.SslState.ForceAuthentication(Boolean receiveFirst, Byte[] buffer, AsyncProtocolRequest asyncRequest)
3:31:18 AM    at System.Net.Security.SslState.ProcessAuthentication(LazyAsyncResult lazyResult)
3:31:18 AM    at System.Net.Security.SslStream.AuthenticateAsClient(String targetHost, X509CertificateCollection clientCertificates, SslProtocols enabledSslProtocols, Boolean checkCertificateRevocation)
3:31:18 AM    at MailClient.Smtp.SmtpSendCommand.Connect(WorkerStatus status)
3:31:18 AM    — End of inner exception stack trace —
3:31:18 AM    at MailClient.Smtp.SmtpSendCommand.Connect(WorkerStatus status)
3:31:18 AM    at MailClient.Smtp.SmtpSendCommand.Execute(WorkerStatus status)
3:31:18 AM    at MailClient.Commands.Command.Process(WorkerStatus status)
3:31:18 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/
3:31:18 AM [email protected] [IMAP]  Synchronizing subfolders: Done
3:31:18 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/Inbox
3:31:18 AM [email protected] [IMAP]  Synchronizing subfolders: Done
3:31:18 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/Dr. Fox
3:31:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
3:31:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/Mom and Dad
3:31:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
3:31:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/Product Info
3:31:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
3:31:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/USNA
3:31:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
3:31:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/[Gmail]
3:31:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
3:31:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/Mom and Dad/Taxes
3:31:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
3:31:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/[Gmail]/Trash
3:31:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
3:31:39 AM [email protected] [GData]  Synchronizing folder list
3:32:01 AM [email protected] [GData]  Synchronizing folder list
3:32:01 AM [email protected] [GData]  Synchronizing folder ‘[email protected]/Contacts/’
3:40:56 AM [email protected] [SMTP]  Connecting: To [email protected]
3:41:18 AM [email protected] [SMTP]  MailExceptions.ConnectionException: Connection failed due to the following reason: 
3:41:18 AM     “The handshake failed due to an unexpected packet format.” —> System.IO.IOException: The handshake failed due to an unexpected packet format.
3:41:18 AM    at System.Net.Security.SslState.StartReadFrame(Byte[] buffer, Int32 readBytes, AsyncProtocolRequest asyncRequest)
3:41:18 AM    at System.Net.Security.SslState.StartReceiveBlob(Byte[] buffer, AsyncProtocolRequest asyncRequest)
3:41:18 AM    at System.Net.Security.SslState.CheckCompletionBeforeNextReceive(ProtocolToken message, AsyncProtocolRequest asyncRequest)
3:41:18 AM    at System.Net.Security.SslState.StartSendBlob(Byte[] incoming, Int32 count, AsyncProtocolRequest asyncRequest)
3:41:18 AM    at System.Net.Security.SslState.ForceAuthentication(Boolean receiveFirst, Byte[] buffer, AsyncProtocolRequest asyncRequest)
3:41:18 AM    at System.Net.Security.SslState.ProcessAuthentication(LazyAsyncResult lazyResult)
3:41:18 AM    at System.Net.Security.SslStream.AuthenticateAsClient(String targetHost, X509CertificateCollection clientCertificates, SslProtocols enabledSslProtocols, Boolean checkCertificateRevocation)
3:41:18 AM    at MailClient.Smtp.SmtpSendCommand.Connect(WorkerStatus status)
3:41:18 AM    — End of inner exception stack trace —
3:41:18 AM    at MailClient.Smtp.SmtpSendCommand.Connect(WorkerStatus status)
3:41:18 AM    at MailClient.Smtp.SmtpSendCommand.Execute(WorkerStatus status)
3:41:18 AM    at MailClient.Commands.Command.Process(WorkerStatus status)
3:41:18 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/
3:41:18 AM [email protected] [GData]  Synchronizing folder list
3:41:18 AM [email protected] [IMAP]  Synchronizing subfolders: Done
3:41:18 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/Inbox
3:41:18 AM [email protected] [IMAP]  Synchronizing subfolders: Done
3:41:18 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/Dr. Fox
3:41:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
3:41:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/Mom and Dad
3:41:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
3:41:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/Product Info
3:41:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
3:41:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/USNA
3:41:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
3:41:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/[Gmail]
3:41:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
3:41:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/Mom and Dad/Taxes
3:41:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
3:41:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/[Gmail]/Trash
3:41:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
3:41:39 AM [email protected] [GData]  Synchronizing folder list
3:42:01 AM [email protected] [GData]  Synchronizing folder list
3:42:01 AM [email protected] [GData]  Synchronizing folder ‘[email protected]/Contacts/’
3:42:01 AM [email protected] [GData]  Synchronizing folder ‘[email protected]/[email protected]/’
3:50:56 AM [email protected] [SMTP]  Connecting: To [email protected]
3:51:18 AM [email protected] [SMTP]  MailExceptions.ConnectionException: Connection failed due to the following reason: 
3:51:18 AM     “The handshake failed due to an unexpected packet format.” —> System.IO.IOException: The handshake failed due to an unexpected packet format.
3:51:18 AM    at System.Net.Security.SslState.StartReadFrame(Byte[] buffer, Int32 readBytes, AsyncProtocolRequest asyncRequest)
3:51:18 AM    at System.Net.Security.SslState.StartReceiveBlob(Byte[] buffer, AsyncProtocolRequest asyncRequest)
3:51:18 AM    at System.Net.Security.SslState.CheckCompletionBeforeNextReceive(ProtocolToken message, AsyncProtocolRequest asyncRequest)
3:51:18 AM    at System.Net.Security.SslState.StartSendBlob(Byte[] incoming, Int32 count, AsyncProtocolRequest asyncRequest)
3:51:18 AM    at System.Net.Security.SslState.ForceAuthentication(Boolean receiveFirst, Byte[] buffer, AsyncProtocolRequest asyncRequest)
3:51:18 AM    at System.Net.Security.SslState.ProcessAuthentication(LazyAsyncResult lazyResult)
3:51:18 AM    at System.Net.Security.SslStream.AuthenticateAsClient(String targetHost, X509CertificateCollection clientCertificates, SslProtocols enabledSslProtocols, Boolean checkCertificateRevocation)
3:51:18 AM    at MailClient.Smtp.SmtpSendCommand.Connect(WorkerStatus status)
3:51:18 AM    — End of inner exception stack trace —
3:51:18 AM    at MailClient.Smtp.SmtpSendCommand.Connect(WorkerStatus status)
3:51:18 AM    at MailClient.Smtp.SmtpSendCommand.Execute(WorkerStatus status)
3:51:18 AM    at MailClient.Commands.Command.Process(WorkerStatus status)
3:51:18 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/
3:51:18 AM [email protected] [GData]  Synchronizing folder list
3:51:18 AM [email protected] [IMAP]  Synchronizing subfolders: Done
3:51:18 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/Inbox
3:51:18 AM [email protected] [IMAP]  Synchronizing subfolders: Done
3:51:18 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/Dr. Fox
3:51:18 AM [email protected] [IMAP]  Synchronizing subfolders: Done
3:51:18 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/Mom and Dad
3:51:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
3:51:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/Product Info
3:51:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
3:51:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/USNA
3:51:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
3:51:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/[Gmail]
3:51:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
3:51:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/Mom and Dad/Taxes
3:51:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
3:51:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/[Gmail]/Trash
3:51:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
3:51:39 AM [email protected] [GData]  Synchronizing folder list
3:52:00 AM [email protected] [GData]  Synchronizing folder ‘[email protected]/Contacts/’
4:00:56 AM [email protected] [SMTP]  Connecting: To [email protected]
4:01:18 AM [email protected] [SMTP]  MailExceptions.ConnectionException: Connection failed due to the following reason: 
4:01:18 AM     “The handshake failed due to an unexpected packet format.” —> System.IO.IOException: The handshake failed due to an unexpected packet format.
4:01:18 AM    at System.Net.Security.SslState.StartReadFrame(Byte[] buffer, Int32 readBytes, AsyncProtocolRequest asyncRequest)
4:01:18 AM    at System.Net.Security.SslState.StartReceiveBlob(Byte[] buffer, AsyncProtocolRequest asyncRequest)
4:01:18 AM    at System.Net.Security.SslState.CheckCompletionBeforeNextReceive(ProtocolToken message, AsyncProtocolRequest asyncRequest)
4:01:18 AM    at System.Net.Security.SslState.StartSendBlob(Byte[] incoming, Int32 count, AsyncProtocolRequest asyncRequest)
4:01:18 AM    at System.Net.Security.SslState.ForceAuthentication(Boolean receiveFirst, Byte[] buffer, AsyncProtocolRequest asyncRequest)
4:01:18 AM    at System.Net.Security.SslState.ProcessAuthentication(LazyAsyncResult lazyResult)
4:01:18 AM    at System.Net.Security.SslStream.AuthenticateAsClient(String targetHost, X509CertificateCollection clientCertificates, SslProtocols enabledSslProtocols, Boolean checkCertificateRevocation)
4:01:18 AM    at MailClient.Smtp.SmtpSendCommand.Connect(WorkerStatus status)
4:01:18 AM    — End of inner exception stack trace —
4:01:18 AM    at MailClient.Smtp.SmtpSendCommand.Connect(WorkerStatus status)
4:01:18 AM    at MailClient.Smtp.SmtpSendCommand.Execute(WorkerStatus status)
4:01:18 AM    at MailClient.Commands.Command.Process(WorkerStatus status)
4:01:18 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/
4:01:18 AM [email protected] [GData]  Synchronizing folder list
4:01:18 AM [email protected] [IMAP]  Synchronizing subfolders: Done
4:01:18 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/Inbox
4:01:18 AM [email protected] [IMAP]  Synchronizing subfolders: Done
4:01:18 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/Dr. Fox
4:01:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
4:01:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/Mom and Dad
4:01:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
4:01:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/Product Info
4:01:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
4:01:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/USNA
4:01:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
4:01:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/[Gmail]
4:01:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
4:01:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/Mom and Dad/Taxes
4:01:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
4:01:19 AM [email protected] [IMAP]  Synchronizing subfolders: For folder [email protected]/[Gmail]/Trash
4:01:19 AM [email protected] [IMAP]  Synchronizing subfolders: Done
4:01:39 AM [email protected] [GData]  Synchronizing folder list
4:02:00 AM [email protected] [GData]  Synchronizing folder list
4:02:01 AM

Hello nobrien,
please try making exceptions in Windows firewall and your Anti-virus software for eM client.

Regards,
Olivia

Please help me understand why that is necessary.  I haven’t had to do that with any other mail client.

The connection to the server can be sometimes detected incorrectly as a dangerous one and blocked. You can just try pausing them for a while to see if that fixes the issue.

Regards,
Olivia