Error IMAP server refuses to import one or more E-Mails.

Help!  What does this mean?  It stops me from composing and sending any emails.  It stops me in the middle with that error.  I will also get the message "an error occurred inside the server which prevented it from fulfilling the request".  I get these exact same messages no matter what browser I use. I cleared the cache and cookies on my Edge browser and still get these messages. I have closed down and cold re-booted multiple times.  Now what? I'm dead in the water and I need my email!!