SMS message sent via email bounced
I send a txt message via email to email@example.com and receive this response:
This Message was undeliverable due to the following reason: the subscriber has restricted e-mail to firstname.lastname@example.org Please reply to Postmaster@txt.att.com if you feel this message to be in error.
A similar question from 7 years ago said to go to http://mymessages.wireless.att.com/ to fix the problem, but that site isn't there anymore. What is the new solution for this issue? Where can I access the unblock options?