A week ago my Thunderbird stopped working. Today I made a full reset (uninstalling, removing all data from appdata etc) and installed the current version (78.1.1 x64, Windows 10, en-US).
I'm unable to add any mail account, the server configuration (STARTTLS, ports, ...) is detected but when I click "done" I get the error my login infformation is wrong. I added the same account I tried to add (at least ten times now) to gMail on my phone and it works fine.
IMAP is enabled on my mail server, the login information are correct (checked multiple times) and the autoconfiguration is fine.
Any ideas? Thanks!