Can't Send Msg's Exchange 2003 (2003 small business edition)

i just setup a exchange server and i can receive mail just fine but when any user tries to send a email msg (to anyone) we get the following msg.

There was a SMTP communication problem with the recipient's email server. Please contact your system administrator.
  <domainishere.com #5.5.0 smtp;550-5.7.1 [Extrnal ip address is here] The IP you're using to send email is not authorized > 


Could it be a problem with my ISP.. it is AT&T by the way..... I also tried to change the delivery settings in the SMTP virtual server and that didnt work .. What could this msg mean?
LVL 1
ncottonAsked:
Who is Participating?
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.

isaman07Commented:
It means your ISP is blocking outgoing port 25. Contact them to make sure.
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
ncottonAuthor Commented:
That is what I was thinking. I will contact them when they are open for questions.. lol
0
isaman07Commented:
BTW, just curious, do you have your DNS configured properly? Like do you have your MX record set in your DNS?
0
ncottonAuthor Commented:
Yeah I have a MX record.
0
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 Protocols

From novice to tech pro — start learning today.