Using Classic Outlook on Windows for personal email, calendar, and contact management
I think the problem is unsuccessful logins. I got a lot of unsuccessful hacking logins. When that happens, it seems Outlook will disable the app password. Creating a new app password fixes the problem, until more failed logins come in and disable the new app password. Very annoying. Microsoft needs to provide a solution: sending alerts on unsuccessful logins and give owners an option not to disable the app password (when owner decides the app password is still good.) Plus, make the app password much harder (currently only 16 lower case letters.)