did you do some sort of security "checkup" on the office web site. WE appear to get lots of issues with folk applying "recommended" security changes in those checkups without fully understanding what they mean to them.

Such things as enabling two factor authentication and not creating application passwords, disabling less secure apps settings then trying to use a connection method other than oAuth.

Matt: When I logged back into outlook online I had a message that my password was expiring today. So I changed it and everything is working okay now. Thanks for your help. I should probably be using Outlook since my organization is paying for it, but I have gotten used to Thunderbird, I have a zillion folders and filters, etc., and I like the way it is looks.

I know the feeling about "probably should"!