I am using Win 7. Suddenly, Thunderbird stopped downloading emails from my in-house Dovecot IMAP4 server. This did NOT coincide with a software update, as far as I can tell. It happened on 14th Feb. I looked at the logs which did not help. Also, Thunderbird displayed no error message. It just hung in the state "connected to <server name>". I was at a total loss, so I downloaded Thunderbird (same version) on my Win 10 laptop. After it downloaded the 40k+ mails on my IMAP server, I checked the inbox. It downloaded all emails up to date (21st Feb). I had set up all server settings exactly the same on the two machines. But the log files are different. I can't really understand the log files, and I can't see any time stamps, but I can see that the Win 10 machine logs in successfully and the Win 7 machine doesn't. Naturally I have tried rebooting my PC. I have attached images of the two log files.