I set up my mail server with Postfix (MTA) and Dovecot (IMAP, POP3). When I tested my installation with an open source webmail interface everthing has been working well: login with username and password, receive mails (port 993, ssl/tls) and send mails (port 587, starttls). Today I started testing local clients beginning with Thunderbird. Here I get an error message like this: Click Me.
In Dovecot I have already changed
ssl_protocols = !SSLv3 !SSLv2
to
ssl_protocols = TLSv1.2 TLSv1.1 TLSv1 !SSLv3 !SSLv2
Moreover I tried to deactivate the OCSP certificate validation in Thunderbird (Settings > Enhanced > Certificates > Validation)
But the issue keeps existing :( Anyone here to help me please?
These answers are provided by our Community. If you find them useful, show some love by clicking the heart. If you run into issues leave a comment, or add your own answer to help others.
From the question linked here and other conversation on the internet, it seems as if there is a bug in Thunderbird. It looks like Thunderbird fails to prompt the user to accept a self-signed certificate.
One work around seems to be importing the certificate manually through Thunderbird’s certificate setting menu. You can find it through Preferences > Advanced > Certificates > View Certificates: