But that is the issue. Nothing pops up. Thunderbird only claims that he couldn’t successfully verify the password. Once 2FA was disabled, password is accepted. With 2FA password is not accepted. That’s it.
Looks like Thunderbird is not able to recognize the switch to 2FA and is not triggering properly the window. Maybe if I deleted the mail account and set it anew it would work, but for existing account it doesn’t work correctly.
It wouldn’t be such a problem, if there was a setting for gmail, so we could for example refresh or purge current allowance, so we could trigger a new authentication window.
I don’t understand. How? There is no OAUTH2 to set up anywhere.
Perhaps an easier solution, visit your myaccount.google.com page, go to the Security tab, and create an App Password. Use that app password within Thunderbird and other mail clients to get and send emails, as not all will support OAuth2.