What is the authentication method for the incoming and outgoing servers? It should be OAuth2, and the account password should be entered in an OAuth browser window, not the usual TB password prompt.

what is oauth browser window? ive tried all the pass word types with my password. with oauth2 tb puts some increddibly long string and i can't change it. my smtp is set at oauth2 and the pass word is my normal password

On the first connection, the OAuth window appears like a browser window with an address bar pointing to an MS site. The token that's stored in Saved Passwords on successful authentication is a long string of characters. Just as with a regular password, if the token is deleted, and TB restarted, the browser window appears where you enter the account password.