problem with IMAP connection to zoho

i cannot connect to zoho for email.  I see many other questions like this, but the conversation always stops before a solution is given.

Set up using parameters from zoho.  Never connects normally.  If I run diagnostics it will fail, using Fix will then successfully work.  Close the Accounts dialog, send/receive =nothing.  Back to Tools/Accounts and Diagnostic fails again…

Details
connecting via IMAP
using  imap.zoho.com  port 993
SMTP works OK diagnostic

Win 10, using windows firewall with exception for C:\Program Files (x86)\eM Client\MailClient.exe

Using Panda Free antivirus.  Don’t see a way to make an exception for a given program.

Turned off both Firewall and AV and same behavior.

LOG
[I have 2 email accounts:  jorisfamily.com which is hosted by godaddy and works OK.  meevaluators.com which is the zoho account that does not work]

7:10:06 PM Online state: changed to online due to NetworkAvailability
7:10:06 PM Jorisfamily.com Google Calendar [IMAP]  Synchronizing subfolders: For folder Jorisfamily.com Google Calendar/
7:10:07 PM meevaluators.com [IMAP]  Synchronizing subfolders: For folder meevaluators.com/
7:10:07 PM meevaluators.com [IMAP]  MailExceptions.ConnectionException: Failed opening connection to server. —> System.Net.Sockets.SocketException: No such host is known
7:10:07 PM    at System.Net.Sockets.TcpClient…ctor(String hostname, Int32 port)
7:10:07 PM    at MailClient.Imap.Base.Connection.<>c__DisplayClassa.b__9()
7:10:07 PM at MailClient.Imap.Base.Connection.Connect(Func`1 getStream)
7:10:07 PM at MailClient.Imap.Base.Connection.Connect(String receiveHost, Int32 receivePort, Boolean explicitSsl)
7:10:07 PM at MailClient.Imap.ConnectionPoolEntry.Reconnect()
7:10:07 PM — End of inner exception stack trace —
7:10:07 PM at MailClient.Imap.ConnectionPoolEntry.Reconnect()
7:10:07 PM at MailClient.Imap.ConnectionPoolEntry.Connect()
7:10:07 PM at MailClient.Imap.ConnectionPool.AcquireConnection(Folder mailFolder, Boolean idle, Boolean forStore)
7:10:07 PM at MailClient.Imap.ConnectionContext…ctor(ImapAccount account)
7:10:07 PM at MailClient.Imap.Synchronizer.SynchronizeFoldersCommand.ExecuteInternal(WorkerStatus status)
7:10:07 PM at MailClient.Imap.Synchronizer.ImapCommand.Execute(WorkerStatus status)
7:10:07 PM at MailClient.Commands.Command.Process(WorkerStatus status)
7:10:09 PM Jorisfamily.com Google Calendar [IMAP] Synchronizing subfolders: Done
7:10:09 PM Jorisfamily.com Google Calendar [IMAP] Synchronizing subfolders: For folder Jorisfamily.com Google Calendar/Archives
7:10:09 PM Jorisfamily.com Google Calendar [IMAP] Synchronizing subfolders: Done
7:10:09 PM Jorisfamily.com Google Calendar [IMAP] Synchronizing messages: For folder Jorisfamily.com Google Calendar/Inbox
7:10:11 PM Jorisfamily.com Google Calendar [IMAP] Synchronizing messages: Done