RBL IP Unblock / Delist request
We recently encountered any issue where our email server was compromised, however, it was later resolved within a twenty-four hour period. Yet, AT&T’s email server are now blocking us and it would appear that there is no way for them to resolve it. All non-AT&T emails go through without incident except emails which are affiliated with AT&T.
The mail system
553 5.3.0 flpd600 DNSBL:RBL 521< 126.96.36.199 >_is_blocked. For assistance forward this error to [email scrubbed]
I have been going through this issue for the last six weeks regarding emails being undeliverable for our email server. I have sent multiple emails to [email scrubbed]t. The reply emails from [email scrubbed]t report back that our email server is not blocked or on their blacklist. However, sending an email to anyone who has an att.net, pacbell.net or sbcglobal.net, etch. immediately bounces back with the above failure.