I recieve these undeliverable messa

[glifex]

I recieve these undeliverable messages alot after switching over to exchange. The email address we try to send to is a valid emil address. Can someone please help.

Thanks
Will


This is the undeliverable message i get back:

Your message

To: user@their.domain.com
Subject: Test
Sent: Wed, 28 May 2003 15:48:05 -0400

did not reach the following recipient(s):

user@their.domain.com on Wed, 28 May 2003 15:49:57 -0400
There was a SMTP communication problem with the recipient's email server. Please contact your system administrator.
<my.server.com #5.5.0 smtp;550 Relaying not allowed>