“Thunderbird stopped working for me on March 29, 2021. I finally realized it is a security authentication issue with my POP3 protocol. I started a new Thunderbird account with the same name, but IMAP protocol. I understand Thunderbird does not yet work with the "OAuth" authorization that AT&T wants to use, but I obtained a Secure Mail Key from AT&T.net (to use with the "Normal Password" Authorization protocol of Thunderbird) and put it in the Thunderbird box asking for a password while trying to access my old POP3 E-mail. It then downloaded almost 3,000 E-mails, but in one folder, not in the many sub-folders I had placed them in with the old POP3 account over the years. -- Can I somehow get AT&T to recognize and download just new files to my old POP3 account, or is that not possible? Would I have to delete the new IMAP account, change the old account from POP3 to IMAP protocol, and download again? I really want to use the POP3 protocol, to keep all E-mail control and files on my desktop computer, without accessing E-mail from other devices. Thank you sincerely for any help you can offer! Dan