my ussers cannot deliver to sbcglobal.net or prodigy.net
NDR generated to recipients saying..
Your message did not reach some or all of the intended recipients.
Sent: date & time
The following recipient(s) cannot be reached:
firstname.lastname@example.org on such date & time
The message cannot be delivered due to a configuration error on the server.
Please contact your Administrator
<mydomain #5.3.0 smtp; 553 5.3.0 flpi095 - m99l6vr30128001, DNSBL :521<188.8.131.52 >_blocked. _For information_see_http://att.net/blocks
when checking this code with att.net.. I did not see the match. Please help.
We only filter incoming mails. .