We suddenly can't authenticate into Thunderbird using email address from a Google Admin account we administer. When we try it with a normal Gmail account, it works fine. Thunderbird detects IMAP with Oauth2 for the Gmail account but POP3 for the Google Admin account and doesn't have Oauth2 as an option in the manual configuration. When you click 'Done' after the Google Admin account's auto detection, it gives you "Unable to log in at server. Probably wrong configuration, username, or password." Both the individual mail account and the Google Admin settings have POP and IMAP access enabled. I've disabled the antivirus and the Windows firewall and am completely at a loss at this point.