SMTP SocketException problem

I love emClient, but have been having repeated, intermittent issues with outgoing mail, specifically SMTP issues as shown in the following log entry:
9:00:21 PM GMail [SMTP]  MailClient.Accounts.SocketException: Connection failed due to the following reason: 9:00:21 PM     “A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond 209.85.144.109:587”
9:00:21 PM    at MailClient.Protocols.Smtp.SmtpSendCommand.Connect(WorkerStatus status)
9:00:21 PM    at MailClient.Protocols.Smtp.SmtpSendCommand.Execute(WorkerStatus status)
9:00:21 PM    at MailClient.Commands.Command.Process(WorkerStatus status)
9:00:21 PM GMail [SMTP]  Connecting: To GMail

The problem eventually goes away on its own, but will last for hours at a time, usually overnight. It affects both GMail accounts I use with emClient, sometimes but not often at the same time. 

Thanks very much for any help you can provide. 

same issue here on both gmail smtp servers. Seem its global issue, and other mail clients have same issues:(

Hello Mark,
can you try adding eM Client to exceptions in your Firewall and Antivirus software and see if the issue persists?

Regards,
Olivia

Hello,
it look lik issue was with gmail smtp server DNS record in our region. Was forced to enter IP adress to make it working.

Thank you, Olivia. I made those changes in both the firewall and antivirus and everything was fine until just now, when both GMail accounts began having the same problem again.

I forgot to note that the “Diagnose” button in the Accounts panel is greyed out for both accounts; perhaps that is something that is GMail specific. Changing ports and security policies (SSL/TLS) in all combinations does not help.

Well the non-sent email was sent immediately after I disabled real-time protection by the antivirus software (Avira free). For some reason the exceptions aren’t working, obviously. If the problem continues I’ll either switch antivirus programs or just disable real-time protection as necessary when outgoing emails are being blocked. If you have any other suggestions, please let me know. Thanks very much.

Sorry about the multiple responses. This time turning off real-time antivirus protection didn’t work, so I’m back to square one. I suppose I’ll need to move away from emClient if there’s no solution, which would be too bad.