Email to Text ([email scrubbed]) Failing

How do you know they're being rejected?  Are you getting a message?  What is that message? 

I have contacted AT&T in the past when this has happened and they reply that it was been corrected.   This in about 3 months it starts again.   Now I am not getting any reply or action from AT&T as if the email request is being ignored.   The email failure I get back from AT&T is:

Your message couldn't be delivered. Despite repeated attempts to contact the recipient's email system it didn't respond.

Contact the recipient by some other means (by phone, for example) and ask them to tell their email admin that it appears that their email system isn't accepting connection requests from your email system. Give them the error details shown below. It's likely that the recipient's email admin is the only one who can fix this problem.

For more information and tips to fix this issue see this article: https://go.microsoft.com/fwlink/?LinkId=389361.

I'm confused... you said you were sending from your g-mail account, but the message you just quoted is from Microsoft.  How, exactly, are you sending this message?

I have tried both outlook.com and gmail.com and they both are being blocked. 

We're here to help with your email to text concerns relangle.

You can reach out to our block list group by emailing abuse_rbl@abuse-att.net to help investigate and help take action accordingly. 

If you have any additional concerns, please feel free to reach out to us. 

Marilyn, AT&T Community Specialist

That's very nice, ATThelp, but totally non-sequitur as the poster is using someone else's mail servers so has no standing with the RBL list team, they'll just delete any e-mail he sends them as non-actionable.