Outlook Mail Will No Longer Open

Hello, everyone....

After many years of trouble-free Outlook Mail use, about 6 weeks ago my account refused to open anymore.  It recognizes my username and password, but then the "blue envelope opening" thing just keeps doing that indefinitely (for hours, if I let it).  Technical mumbo-jumbo by two Microsoft "helpers" is no help at all (Guys, most of us have no idea what a "noom" might be).

Any simple advice from a plain-speaking person will be very much appreciated.

Thanks,

Doug in Chicago