Hello, I have a problem with Thunderbird that I don't understand and can't solve. Thunderbird can't connect to my IMAP account on the remote server perfectly even after a clean install. Incoming emails are downloaded, but only 82 out of 5600 outgoing emails. All login details are correct, I tried STARTTLS settings on the correct ports, but there is no change. I see in the Activity Manager that the connection between the server and the client is lost several times a minute. There is no network error, both I and the internet service provider have checked the connection. The client is running the Win11 operating system.

Robert