Same problem here...sending or receiving a message to/from someone with @att.net email address is blocked....I sent an email to exedelistens with content of error message which says it'a blocked because of "Abuse"...this is the error message:
This message was created automatically by the mail system (ecelerity).
message that you sent could not be delivered to one or more of
its recipients. This is a permanent error. The following address(es)
>>> firstname.lastname@example.org (after MAIL FROM):
550-22.214.171.124 blocked by ldap:ou=rblmx,dc=att,dc=net 550 Error - Blocked
for abuse. See http://att.net/blocks
Hi Nancy, I would suggest giving our Migration team a call at 1-855-463-9333 so they can address these email concerns with ATT. They would also be able to offer information to our engineers if there does seem to be an known issue regarding emails to ATT or not. Thank you