That project looks like it uses SSL/TLS so if your certificate is self signed you'll need to add an exception [1] Thunderbird doesn't prompt for this while con

That project looks like it uses SSL/TLS so if your certificate is self signed you'll need to add an exception [1] Thunderbird doesn't prompt for this while connecting like a web browser does. It fails to connect without a clear warning in this case. Full shameful disclosure: Since my backup is only locally accessible on a trusted network I used insecure IMAP on port 143 [1]: https://serverfault.com/questions/532172/thunderbird-not-trusting-certificate-signed-with-self-signed-authority https://serverfault.com/questions/532172/thunderbird-not-tru...