exchange server suddenly not connecting to outlook app on computer - won't sync emails

Email was a Go Daddy and switched to Microsoft 365 about a year ago.  The following was written for me by tech support guy who suggestested asking community: 

"I have an exchange server from go daddy and migrate my emails to M365, I wanted to set up on my Outlook app but its not recognizing my credentials"

The "need password" tab is appearing but when click on it a box appears to start open for a milli-second then disappears.  

Please help me.  Thanks!

-- Tom