I've got a bit of a confusing issue here, we're an ISP and we relay mail for a whole bunch of folks. The other day one of them calls us and says their mail is getting bounced by our server. So I have a look on the server and I see loads of mail from their domain going through, I dig a bit deeper and I find that only sales[at]jimshop.com is getting blocked by spamcop wheras everyone else [at]jimshop.com is getting through.
The IP address for jimshop.com is on the spamcop list so I was thinking it might be the recipient server that is blocking it but the bounceback message is coming from our outbound smtp server
also, it's being blocked because it sent to a spam trap, what actually is a spam trap?