I recently installed a new SBS 2003 R2 server at my company about 3 weeks ago. Everything has been fine but today a user told me all emails to a particular user were being rejected with the error that is attached. Does this mean my company's public IP has been blacklisted, is it a permissions issue, is it on AT&T's end, my ISP's end? A little light would be helpful. THanks!
FROM : System Administrator
SUBJECT : Undeliverable:FW: TOMRI rent to TREHC
BODY OF MESSAGE (has been edited for privacy):
Your message did not reach some or all of the intended recipients.
Subject: FW: TOMRI rent to TREHC
Sent: 10/9/2008 11:01 AM
The following recipient(s) could not be reached:
XXXX@sbcglobal.net on 10/9/2008 11:01 AM
The message cannot be delivered due to a configuration error on the server. Please contact your Administrator.
<XXXX.com #5.3.0 smtp;553 5.3.0 flpi127 - m99H1wgD009159, DNSBL:521< MY.PUBLIC.IP.ADDRESS >_is_blocked.__For_information_see_http://att.net/blocks>