Problem sending to AOL.COM

[NewfiePower]

We are having some serious problems trying to send e-mails to anybody with an AOL.COM address. Sending to all other domains is working fine. This problem only starting happening recently out of the blue. The error message I'm getting from our GWIA is:

Detected error on SMTP command
Command: DATA
Response: 500 SYNTAX ERROR, COMMAND UNRECOGNIZED

Does anybody have any ideas or can help?????

James

 

[NewfiePower]

I found out the problem. Our ISP was blocking reverse DNS lookup.

 

[ronnetp]

I am having the same problem suddenly
smtp;500 SYNTAX ERROR, COMMAND UNRECOGNIZED

I dont have anything configured on My Reverse Lookup zone

do I need to configure them?

 

[bkast3]

I know that you wrote that you found out why, but we had the same issue and went back and forth with our internet host on who's problem it was. We finally decided to bring our dns in house and keep it on the other side of the firewall. If you need any additional help let me know.

 

[NewfiePower]

Our Internet host did not have a problem with allowing reverse DNS lookup on our domain name. Thanks Allstream.