Topic: Remote host claims server is relaying mail

[ddougan]

One of my clients is getting the following message:

Remote host said: 550 relaying mail to cxxyyzz.com is not allowed (domain name changed)

Now this server has been running successfully for over three years, and has the ISP's mail server name in the server manager field labelled: "Address of Internet provider's mail server". The failing domain (which is the only one demonstrating this problem) is hosted by the same ISP, in another province. I'm wondering if the last point is related to why the recipient server thinks it is a relay problem.

Can anyone shed any light on what is happening here?

thanks,

Des

[cc_skavenger]

Is it possible that they started doing SPF.  What about your DNS PTR records, are they showing arpa addresses instead of the domain.

Just a couple of thoughts.