Hello there If you cannot accept the situation or you can t get in that password field to fill in that correct password to get that mail? Things like outdated passwords or wrong input from old passwords or other situations are mostly the trick of finding out and entering that field then with success ain’t possible then. Did you already tried to solve this by deleting the password and restart that Thunderbird program again. try to check these incoming and outgoing settings see if they are working well ,go to the outgoing settings for mail SMTP settings. Be sure that all settings are oké and passwords are set to the normal use of them. If you use Oauth02 be sure that you hereby use a normal password and not a generated one from a password generator. And be sure of that the use of cookies is enabled to save these cookies there. I mean these both things do come together for the good use of them. Also to complete the answer on this be sure that Thunderbird is updated to the latest version. Server sided problems can be a there , but first try to work out the mentioned subjects. Options for starting up in safe modus can solve . Hereby please try to see if that is correct and does solve situations here. Password tools and extensions are disabled then. Something might be in the way of disturbing that login process by having no good add ons or extensions over there. Questions are open. https://support.mozilla.org/en-US/kb/troubleshoot-mode-thunderbird Greetings googlethunderbird.