Thunderbird suddenly stopped working for this "att.net" email at the end of July. Per the online support, I deleted the account in Thunderbird. When trying to add the account back, the "configuration found in Mozilla ISPDB" worked, but now gets an authentication error (probably wrong configuration) when I try to add it back in. I can reach my att.net emails directly (account login and password work), but Thunderbird will not activate or access this ATT.NET account. (My other Thunderbird emails are working.) Please help.