Incoming email to xfinity email account from specific safe domain reported as SPAM

All emails I have recently sent to my Comcast email address from a personal email domain address are being reported as SPAM, also abuse complaints have been sent to my domain host. As a result, the host has suspended the email account. I had to appeal the suspension to get the account reactivated.

In the online xfinity email browser, I have made the subject domain a trusted sender in filter rules and marked the emails as "not spam" in the spam folder.

Why has Xfinity mail suddenly started flagging my person email address as spam and sending abuse complaints to my host?  The email address in question has been accepted by my Xfinity email for over 20 years without problem.