March 5, 2018 – We’ve received a few reports of people having issues emailing domains which are handled by Prodigy’s mail servers.  These include the,, and domains as well as and others.  Senders are receiving a failure notice which includes the following error:

Remote host said: 550 5.7.1 Connections not accepted from servers without a valid sender domain.flph829 Fix reverse DNS for


We have looked into the issue and have confirmed that our reverse DNS is working correctly.  The problem is on the Prodigy server side and their servers are unable to look up the correct information for some reason.  There is nothing that we can do to help with this problem from our end.   If you are experiencing this, please inform the recipient and ask them to contact their provider.  If you have the ability to send the them the error through an alternate means, that will help them to report the issue.   We’re hoping that after Prodigy receives enough reports that they will correct the issue on their end.

Here is a link to one of several tests we have run to confirm the issue is not on our side:


Update – March 6, 2018 8:30am – As of this morning, this issue is still ongoing.   We have again reached out to the contacts for to request an investigation.  Again, if you are experiencing this issue, we do request that you ask the recipient (the person with an,, or other domain that is being rejected with this error) and ask them to contact their support as well.

Update – March 7, 2018 2:30pm – This is still an ongoing issue and we have not received any contact from Prodigy.

Update – March 8, 10:45am – The issue is still ongoing and we have requested an escalation from their support.

Update – March 9, 2:40pm – Still ongoing and we have not received any response from AT&T or other providers.  Please contact recipients you are trying to contact (account holders with, addresses) and ask them to contact technical support about this issue.  It seems the only way that the issue will get noticed.

Update – March 10 12:45am – We got word that our blog post here helped a credit union in Louisiana get this issue fixed.  They were experiencing the same problem and were able to get in touch with AT&T to get it handled by using our blog post to prove that it was not an isolated issue.  They have given us the contact they used and we have also reached out to AT&T.  Unfortunately, in over 3 hours we have not received any contact – not even an autoresponse.

Update – March 12, 3:45pm – A kind network operator upstream of us has allowed us to relay, and through them.  This will help some with the problem, but because of SPF records some email may be delivered to the user’s spam folder.   We are still making attempts to get in touch with AT&T, but our please have fallen on deaf ears so far.

Update – March 14, 2:45pm – We have finally received word from an AT&T contact that they have resolved this (Nationwide issue) on their end by opening ports on a firewall being used by some new name servers they have put into service.   We have removed the relay we put in place on the 12th and tested delivery to confirm the fix.   Everything should be working normally now.


If you have any questions about this issue, please email or call 256-547-6817.