August 6, 2007

Is AOL Mail Failing?

I'd like to find out if an e-mail problem I'm seeing is a widespread issue. Most e-mail I send out to AOL customers has been bouncing back for the last several weeks. It comes back with a message from the AOL server that states:

Delay reason: SMTP error from remote mail server after end of data: host []: 421-: (DNS:NR) 421 SERVICE NOT AVAILABLE

My e-mail service tells me it will retry, and the failure messages continue for 72 hours until the system gives up entirely. Is this happening across the Internet and is AOL's mail service failing, or is this something more localized? I'd like to hear from CQ readers if they have had any of these difficulties.

And if you use AOL and have been expecting replies from me, you may not get them until the problem gets resolved one way or another.

UPDATE: The problem appears to have been partly resolved with a DNS refresh by my hosting service. I'll update this if more problems appear.


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Comments (19)

Posted by John Cunningham | August 6, 2007 8:39 AM

Mon Capitaine,
I am one of your most faithful readers, I think, your common sense stands out. I send out lots of email messages for a local Mensa group, a hiking group, and a kayak group, to a fair number of AOL addresses. I haven't seen any bouncebacks from AOL, so I would guess it is a prob with your ISP or maybe your email configs??

Posted by Micah | August 6, 2007 8:46 AM

Hey all,
Yes, Ed, we are having problems, too.
My wife sent out a bunch of stuff Sat. night, and the only two to come back were with AOL addresses. We're in Ohio, but I doubt that has a thing to do with this.
AOL has never been quality.... They are probably still using 286 servers running Prodigy (c) hosting programs!

Posted by Pete Fanning | August 6, 2007 8:51 AM

According to an NSLOOKUP, four hosts respond to the mailin-01 host name, and that IP in your example could have been down at that moment or could have been busy...but as you stated this has been an ongoing other thing to check is your reverse DNS setting, whoever is providing your DNS service.....AOL rejects inbound mail connections from domains that do NOT have reverse DNS (PTR) records configured.....

Posted by Deskmerc | August 6, 2007 8:54 AM

What Pete said. its possible AOL's dns reverse lookups are failing, but double check and make sure that your mail server has a PTR record of some sort, somewhere. If there are multiple mail servers, they all need to have PTR records for the sending IP.

Posted by David Wollstadt | August 6, 2007 8:55 AM

I have sent out a few messages to AOL addresses in the last couple days and have not received the error messages you describe.

Posted by Thanos | August 6, 2007 8:57 AM

There's been a steep upramp of the storm-worm spreading via email the past week, AOL probably has their shields on high to deflect some of the mail storm. If you are sending to a long list you are much more likely to get deflected.

Posted by Ray | August 6, 2007 9:00 AM

You should check with your own ISP to make sure the IP address of the mail server that is talking to AOL's MX server is able to be correctly resolved. If it is, then the problem is on AOL's end. If not, then your ISP likely needs to correct the issue with its own DNS setup.

Hopefully the problem will just go away on its own -- DNS problems often are delayed 24-72 hours due to the caching nature of the system.

Posted by Linh_My | August 6, 2007 9:12 AM

AOL, Earthlink and others block a large number of IP address ranges. If address falls with in one of those ranges, than you can not send eMail to AOL etc. customers. This is in response to "spam."

Someone inside of your range of IP addresses may have sent a few too many "spam" eMails.

Posted by The Florida Masochist | August 6, 2007 9:42 AM


I tried contacting you recently about a mistake in one of your blog posts. No return email was ever received by me from you, but then the post is still incorrect as of today.

There you wrote about Indonesia being a singular example of Muslim democracy in South Asia. This than 10 years after Suharto left office, but more notably you forgot Bangladesh and Malaysia both with Democratically elected governments and Muslim majorities.

I try pointing these things out in private email so fixes can be made. You've gotten 1 or 2 of those before from me. Here it is now for your information.


Posted by avonelle Lovhaug | August 6, 2007 9:45 AM

Be thankful that you get bounceback messages. My emails to AOL accounts simply disappear into an abyss, with no warning to either me or the recipient. They simply do not arrive at the destination. I haven't seen this was other accounts that may think my email is "SPAM". AOL is the only one where I don't see any bounceback messages.

I automatically send emails to AOL accounts using my Yahoo account, which is pretty funny if you think about it. I get TONS of spam from Yahoo accounts.

Posted by Bill | August 6, 2007 9:47 AM

Could be related to an intermittent problem with comcast: newer (3 years?) mail security guidelines call for the receiving MTA to do a reverse DNS check of the SENDING MTA. This is often a problem where the sending site uses auxilliary sending servers (usually for load balancing issues).

Comcast sends instructions in the bounce message; perhaps AOL is finally doing the right thing but not notifying? Usually shows as a permanent failure.

Comcast and AOL, BTW, are among the top spam distributors due to the large number of customers.

If it is this behavior, obnoxious as the lack of notice might be, the web will be better off with broader enforcement. In effect, this addresses the "open SMTP server" problem where you can forge email from any domain.

I'd suggest contacting either your ISP's tech support and AOL's if you have a target that fails that'll call them.

Posted by Rick Moran | August 6, 2007 9:48 AM


In case your email is funky, I accept the invite and will be on at 2:00 PM central.

Posted by Orlin | August 6, 2007 9:54 AM

Yep -- that has been happening more frequently when I send messages to people with AOL addresses. It has been happening for quite some time!

Posted by kimsch | August 6, 2007 10:47 AM

My old address was changed to for aol instant messenger. Might they be doing this elsewhere? AOL, Netscape and CS (compuserve)?

Posted by Judith L | August 6, 2007 10:51 AM

It's been months since I have been able to send to aol without a bounceback.

Posted by Cindy | August 6, 2007 11:22 AM


I have had intermittant problems from my home account with AOL users. However, I suspect that your problem is indeed a reverse DNS look-up problem. A customer of mine had the same issue with their carrier (not Comcast BTW) a couple of weeks back and as soon as the Reverse DNS was listed the problems went away.


Posted by John Steele | August 6, 2007 12:49 PM

This has been happening to me for the past two weeks with my friends who use AOL.

Posted by Helo Pilot | August 6, 2007 1:23 PM

The problem was spelled out for you in the BOUNCE message - if you would have just pasted the URL from the bounce message into your browser, you would have realized the problem...

Reverse DNS - specifically that your mail server lacked a PTR entry in public DNS, was the problem - and no 'DNS Refresh' at your ISP could fix it - that is just the Simpleton explanation...

Posted by Pete Fanning | August 6, 2007 1:45 PM

Well then, I was right the first time :)

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