Contact emails get sent to the junk folder

I am using Apple Mail on a Macintosh running MacOS Big Sur.

The Mail app frequently marks messages as Junk and moves them to the junk folder, even when the sending email address is in my Contacts.

In Mail Preferences I have enable Junk Mail Filter, and exempted "Sender of Message is in My Contacts" and "Sender of Message is in my Previous Recipients".

Does anyone know how to get Mail App to stop sending emails from my listed contacts to the Junk folder?

Thank you.