I upgraded to Thunderbird Version 68.12.1 in March and had to reinstall my email accounts. My Yahoo account installed fine, but my legacy pacbell.net (now through att.com) account keeps getting a configuration, username/password error. I input the username and password that works for all my other devices. Thunderbird was working before the upgrade, I have installed both Version 78.9.1 and Version 78.11.0 hoping that the problem would be fixed, but I still can't install the account.