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I am having trouble while attempting to send a single email to an user. I get a rejection reply as follows:

Your message did not reach some or all of the intended recipients.

   Sent: Wed, 27 Jul 2011 15:56:24 -0400
   Subject: Test

The following recipient(s) could not be reached:
   Error Type: SMTP
   Remote server ( issued an error.
   hMailServer sent: 
   Remote server replied: 421 4.7.1 : (DNS:NR)

Tried 9 time(s)


Troubleshooting using AOL's troubleshooting page, rDNS lookup results are:

RDNS Results

DNS Server Response:

And using NSLOOKUP myself ..

Server:  homeportal

Non-authoritative answer:      name =

When using telnet,

C:\>telnet 25
421 4.7.1 : (DNS:NR)

Connection to host lost.

My hMailServer is set up correctly, is not an open relay, is not used for spam, is not on any blacklists, and so forth.

Any tips on getting AOL mail servers to accept mail? As far as I can tell, everything is being done correctly on my end.

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marked as duplicate by Tom O'Connor Aug 11 '13 at 19:54

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

While it kind of sucks, changing the reverse to match your MX may have more success than having it reverse to your website. Just the nature of the beast these days.

Also, where is the server located, i.e. is it on a residential internet connection? Many of the larger ISP's are quite unkind to mail connections from blocks of IP's allocated to residential users.

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Yes, a residential IP block (AT&T Uverse). However that does not seem to be a stated restriction. In fact, when I use telnet to connect (see above logging) the connection is rejected for reasons of rDNS. – Robert Kerr Jul 28 '11 at 11:22
Right. When i said 'quite unkind' that kind of falls into it - blocking email without overtly stating why, or giving a reason that's actually a misdirection, such as 'we don't like your reverse DNS'. It might be worth contacting AOL postmaster. The one thing I'll give AOL credit for is having a responsive postmaster address. There are real people there who will communicate with you, unlike some email providers <cough>gmail<cough>. – anastrophe Jul 28 '11 at 18:07

It looks like your email server is announcing itself as "homeportal" while your rDNS is identifying itself as "" based upon the information you provided. If that is the case, then that is a mismatch where you might consider changing your email server to announce itself as "" to match up to the rDNS.

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AOL's policy simply states that an rDNS must exist, not that it match anything specific. When using AOL's own tool to verify my server has an rDNS assigned, it reports that it does. – Robert Kerr Jul 28 '11 at 11:21
You might want to have that clarified with them as most systems that do rDNS checks are looking for matches against its host announcements. – user48838 Jul 28 '11 at 12:32

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