SpamCop Emails To Me Bounce in SpamCop Email System & Accounts Posted January 24 On 1/19/2020 at 5:00 PM, Lodewijk said: "Bounce error Your email address, (xxx) has returned a bounce: Subject: Delivery Status Notification (Failure) Reason: 5.1.0 - Unknown address error 550-'Sorry, we do not accept connections from=" I had this happen with my account on gmail. I had to find all the related message in my spam folder and mark them as "not spam" in order to get their spam rules to stop rejecting it. For me, it all started when google changed their rule system and needed every thing to be setup again. So far I have all seems good for me. Hopefully this might help you.