Autocinfiguration is fine, my problem is that once everything is (auto)configurated (correctly, checked this) that the server doesn't accept my login request.
STARTTLS is correct, ports are correct etc. My mail is correct, my password is correct (tried with copy paste) and also with name as username and name@domain aswell (name was also copy pasted).

On 19/07/2020 12:43, Bernardo Reino wrote:

On Sun, 19 Jul 2020, Nils wrote:

This is what my server logs (mail.info, mail.warn) tell me:
root@bgrsld-mail0:~# tail /var/log/mail.info
Jul 17 18:22:08 bgrsld-mail0 postfix/submission/smtpd[8472]: improper command pipelining after EHLO from unknown[192.168.2.110]: QUIT\r\n
Jul 17 18:22:08 bgrsld-mail0 postfix/submission/smtpd[8465]: disconnect from unknown[192.168.2.110] ehlo=1 quit=1 commands=2
[...]

Thunderbird, for some reason, violates the SMTP standard when attempting autoconfiguration. It sends multiple commands ("pipelining") without postfix having announced that it's OK to do so.

You can either do the configuration manually (when Thunderbird fails, I think you can still go to "manual" or "advanced" or whatever button to continue with the configuration), or you could, at least temporarily, disable postscreen (which is the only complaining -- rightly -- about the improper pipelining), and then enable it again once you have configured your account.

You can also read:
https://developer.mozilla.org/en-US/docs/Mozilla/Thunderbird/Autoconfiguration

and set-up the necessary XML file at your server so that Thunderbird can pickup the settings automatically. I've done this for one server, but don't have the details anymore in my head. The link above should explain that all though.

Good luck!
Bernardo