Mail not being recevied by alot of users. ispcp-arpl error returned.

[kaotix]

I have just noticed alot of e-mail going to various addresses on my server are getting returned.

Quote:<abuse@ispcp-arpl.domain.com> (expanded from <abuse@domain.com>):
Host or domain name not found. Name service error for
name=ispcp-arpl.domain.com type=A: Host not found

Final-Recipient: rfc822; abuse@ispcp-arpl.domain.com
Original-Recipient: rfc822;abuse@domain.com
Action: failed
Status: 5.4.4
Diagnostic-Code: X-Postfix; Host or domain name not found. Name service error
for name=ispcp-arpl.domain.com type=A: Host not found

I've searched the forums but only found one post about regenerating config files. This doesn't seem to have anything to do with this and I'm really stuck.
I just created a new e-mail address and that worked fine, both as a forward and a standard mailbox. Can anyone help me out?
Thanks