Split from this thread.
I cannot access my Office 365 mail from Outlook 365 client any more. This has happened on 2 computers.
I can log into my mail with OWA.
Some suggestions I found and tried.
I have deleted profile on one machine and now cannot connect.
I did a full online repair of Office.
On the second I turned off caching and then back on.
Checked for updates on both computers.
You mentioned 2 step verification.
I just turned on 2 factor authentication for my admin account in my tenant yesterday.
I did not turn it on for the account that I am having problems with.
have there been other issues with 2FA?
After I posted, I turned on Multi Factor Authentication on the mail account I am having a problem.
I figured it could not hurt.
So far it has not helped.