Thunderbird can't connect to Dovecot (bad certificate: SSL alert number 42)

[Meikel]

Hello.

Am 14.09.2022 um 13:59 schrieb Christian Mack:
> Sound to me, as if Thunderbird does not know the CA used to (self) sign
> that server certificate.

Following the documentation at

https://community.letsencrypt.org/t/simple-guide-using-lets-encrypt-ssl-certs-with-dovecot/2921

I configured

ssl_cert = </etc/letsencrypt/live/...../fullchain.pem
ssl_key = </etc/letsencrypt/live/...../privkey.pem

to my Let's Encrypt SSL certificates and did a restart of Dovecont and 
at least for one installation of Thunderbird it seems to work again now. 
For the other installations I need to check later at home, but the 
problem seems to be resolved.

Regards,

Meikel