Yahoo connection failed

I get a connection error intermittently when eM Client tries connects to my Yahoo email account.  After I get this error I can look at the account diagnostics and IMAP and SMTP both have a question mark and Unknown showing.  If I run Diagnose they both will then show a check mark and Ok.  I will get a test message and all works fine until I get the error again.  On the General tab for my Yahoo account I have CalDAV and CardDAV unchecked and IMAP and SMTP checked.

Can someone please take a look at the following information and let me know if you have a solution. 

Here is the log file information:

4:30:01 PM [IMAP]  MailClient.Accounts.ConnectionException: 4:30:01 PM (Disconnecting)
4:30:01 PM    at MailClient.Protocols.Imap.ConnectionPoolEntry.Reconnect(CancellationToken cancellationToken)
4:30:01 PM    at MailClient.Protocols.Imap.ConnectionPoolEntry.Connect(CancellationToken cancellationToken)
4:30:01 PM    at MailClient.Protocols.Imap.ConnectionPool.AcquireConnection(Folder mailFolder, Boolean idle, Boolean forStore)
4:30:01 PM    at MailClient.Protocols.Imap.ConnectionContext…ctor(ImapAccount account, Folder folder, Boolean forStore)
4:30:01 PM    at MailClient.Protocols.Imap.Synchronizer.FolderInfo.CreateConnectionContext()
4:30:01 PM    at MailClient.Protocols.Imap.Synchronizer.SynchronizeMessagesCommand.ExecuteInternal(WorkerStatus status)
4:30:01 PM    at MailClient.Protocols.Imap.Synchronizer.ImapCommand.Execute(WorkerStatus status)
4:30:01 PM    at MailClient.Commands.Command.Process(WorkerStatus status)

Hello RGL,

Could we please ask if you have activated the two-step verification on Yahoo? Yahoo has recently made the two-step verification mandatory for all accounts. To set it up, please sign into your Yahoo Account Info page Go to Account Security, turn the two-step verification on and follow the necessary steps to activate it. You will then need to create an app-specific password for eM Client as a 3rd party application. Go to Manage app passwords, click on Other application, fill in eM Client and you will get your password. Use this password for your Yahoo account in eM Client.

More info about enabling two-step verification:
More info about app specific passwords: More details on enabling two-step verification