I am not receiving mail from someone I should be getting it from and I have verified that it has been sent. I believe I may have inadvertently blocked it. How can I see what I have blocked and possibly unblock it?
I think I have inadvertently blocked incoming mail from a source I didn't mean to block. How can I see if this is the case and how can I unblock it?
iMac (21.5-inch Mid 2011)