421 Service Temporarily Unavailable

Hello Experts

I'm working on trouble tickets in my company and ran across one that I'm not sure about solving.  My user didn't tell me which mail program was used, so I listed them both.  I know my company sends out large amounts of email through PowerMTA and I thought maybe we were blacklisted or something, but can't find anything that would support that idea.

So, what do you guys think?  Is this something on my server end or the receiving end?  My diagnostic info is.....

Your message has encountered delivery problems
to the following recipient(s):
email@domain.com
Delivery failed
421 Service Temporarily Unavailable
No recipients were successfully delivered to.
Reporting-MTA: smtp.domain.com
Received-From-MTA: dns; domain.com (unverified [x.x.x.x])
Arrival-Date: Fri, 25 Mar 2011 14:56:35 -0400

Final-Recipient: rfc822; email@domain.com
Action: failed
Status: 5.4.7 (Permanent failure - routing/network: delivery time
expired)
Remote-MTA: dns; cluster4a.us.messagelabs.com (is this some spam agency's dns?)
Diagnostic-Code: smtp; 421 Service Temporarily Unavailable

Any help would be greatly appreciated.

Thanks.
Ray DrummondLan Administrator IIIAsked:
Who is Participating?

[Product update] Infrastructure Analysis Tool is now available with Business Accounts.Learn More

x
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

Glen KnightCommented:
0

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
Email Servers

From novice to tech pro — start learning today.