Problem sending e-mail

Been getting some bounces today… sending from Outlook through mail.mydomain.com I’ve had two returns…

The following recipient(s) could not be reached:

  'someaddress@somewhere.com' on 8/24/2006 6:05 PM
        553 sorry, that domain isn't in my list of allowed rcpthosts (#5.5.3 - chkuser)

Is this a problem with my server or “theirs”?

I have an rcpthosts with all my domains and a tcp.smtp with all my IPs and RELAYCLIENT specified…

Thanks,
Cliff.

I think it’s “their” problem, but I’m not 100% sure. Try sending an email from one of your domains to a gmail account or something.

If this an email you are sending out then I would assume that the rcpthost is on their end since they are receiving the email. So basically I think it’s saying that that email doesn’t exist on the server you are trying to send to.