Apple Mail not sending.receiving email

Yorkster wrote:

I've just "upgraded" to Big Sur, but it would seem that Apple Mail doesn't now work.

I can't receive or send any emails and all of my accounts show a triangle with an exclamation mark inside.

The error when clicked says:

"Connections to the server “mail.mymailserver.co.uk” on the default ports timed out."

Its obvioulsy not the mail server as my iphone, ipad and other apple devices work fine, its just this now OS thats broken Mail.

Any idea what the issue is and how to fix?

Thanks

Delete the account and add it back in.

IMAP stays o the server.

Uninstall AVAST, it is not needed, uses system resources while providing no benefit, and it may cause problems.