Not Receiving Email, Returned to everyone with 550 error

[ajhts]

My exchange 5.5 server on windows NT all of a sudden is rejecting ALL INCOMING email. It is bouncing back to everyone with a 550 Administrative Prohibition.

Does anyone have a clue as to what this means and how to fix it. I have ran all spyware and virus checks and I am clean. Email has been working perfect for a long time and this just happens this morning. Thanks!

AJ

 

[excadmin]

Check with your network team and see if they enable reverse DNS on your mail gateway. That's where I would start.

C

 

[magicka]

THis is due to one of your ISP's servers being listed as a SPAM server!