..mail exchanger or IP address. (#5.4.4) DNS Issue?

[MelvinM]

Hi.

I setup a new Exchange server w/ a Mailsweeper "virus scanner" that fowards the mail to it. I can send and recieve find between my new exchange server and yahoo.com for a while, and then I get this on a delivery failure:

Message from yahoo.com.
Unable to deliver message to the following address(es).

<MelvinM@domainx.com>:
Sorry, I couldn't find a mail exchanger or IP address. (#5.4.4)

But 20 seconds later I can send it through...

I believe this to be a DNS issue. Does this entire entry look valid for one Exchange server? Do I need to specify the &quot;10&quot; since it is the only mail server, or perhaps a setting of &quot;0&quot;?


domainx.com MX preference = 10, mail exchanger = mailserver.domainx.com


Thank you.