Sending of password for user johndoe@gmail.com did not succeed. Mail server pop.gmail.com responded: Username and password not accepted. This error suddenly started. The answer at https://support.mozilla.org/en-US/questions/1309075 *** might be the solution but the Options panel seems to have gone and the online instructions in Thunderbird Help also lead to an outdated layout. More updated instructions would be appreciated and especially if written for a very old senile fool. I see that I set the password for my mail over a decade ago and I didn't know what I was doing then 8-) I can still read my email via Chrome. *** ''If you viewed the password in Saved Passwords, it indicates you're using 'normal password' authentication instead of the preferred OAuth2. First, check that cookies are enabled in TB Options/Privacy or Privacy & Security (TB 78), set the authentication to OAuth2 in Server Settings for the incoming and also in Outgoing Server (SMTP), then delete the passwords in Saved Passwords, restart TB, enter the current working account password in the OAuth browser window when prompted.''