Since I have a personal account, I'm using 'Normal password' authentication for both IMAP and SMTP servers. I've told TBird to use SSL/TLS for IMAP, but can't get that to work for SMTP, so use STARTTLS there. I've got two-step verification enabled, so the password I use in TBird is an 'app password' (see the Microsoft link) Note that when you change at least some of these mail server settings in TBird, they don't take effect until you restart the program.