Over the last few months there have been ongoing mail problems at AOL. These problems are all over the map and are resulting in a lot of delayed and unsent email. People are reporting a number of different error messages from AOL mail servers. These messages don’t seem to always be accurate or correct.
A couple examples:
SMTP error from remote mail server after end of data: host mailin-02.mx.aol.com [64.12.90.65]: 521 5.2.1 
CON:B1) http://postmaster.info.aol.com/errors/554conb1.html reported by the owner of a low volume discussion list with paying subscribers that should have zero complaints.
delivery temporarily suspended: host mailin-01.mx.aol.com[205.188.146.193] refused to talk to me: 421 mtain-dg03.r1000.mx.aol.com Service unavailable – try again later reported by all sorts of senders.
205.188.190.2 failed after I sent the message. Remote host said: 521 5.2.1 “TempFail” reported by a small mail host.
554 mtain-dc03.r1000.mx.aol.com ESMTP not accepting connections reported by an ESP.
421 4.7.0 mtain-dg05.r1000.mx.aol.com Error: too many errors reported by a university, a mailserver vendor and a bunch of ISP and telcos.
This is not a constant or consistent set of errors. It is coming and going, with AOL reporting things are fixed and senders reporting queues emptying. However, every time it seems to be fixed, something else breaks.
There isn’t much anyone outside of AOL can do, though. This has to be fixed internally by their engineers. I’m afraid this is just the result of a highly complex system that is failing due to bit rot, though. Which means only significant investment in time and programming power can fix this for all of us. I do hope I’m wrong.
It’s weird to be writing this blog post the same day I found out that Jay Levitt, one of the original AOL mail system architects has died. I didn’t know Jay well, although he did post a comment here once or twice. I haven’t heard any details, yet, but it’s strange to be writing about AOL mail today.
The specific issue you quote was due to a new anti spam rule last week and has been rolled back since. There shouldn’t be any issues going on over the last few months. If you are aware of anything else, don’t hesitate and contact me directly.
I’ve been hearing about AOL problems for months, and I know that a number of people have been in contact with AOL and been providing evidence of the problems. People have been seeing problems with delivery to AOL since at least August: http://blog.wordtothewise.com/2012/08/aol-bounces-and-false-positives/. There was also a round of problems back in May: http://blog.wordtothewise.com/2012/05/aol-update/
While the underlying reasons for the problems may be different, a lot of people are struggling to deliver real mail to AOL over the last few months.
32,088 messages in the queue while getting:
2012-10-15 13:46:10 SMTP service unavailable: “421 4.2.1 “Service unavailable. Please try again later.”" received from mailin-03.mx.aol.com (205.188.59.193) while connected from (63.241.211.110) to mailin-03.mx.aol.com (205.188.59.193)
This is the same thing that happened to us during the other dates Laura mentions.
I wish they could even get their error messages straight:
—– The following addresses had permanent fatal errors —–
XXXX@aol.com
(reason: 521 5.2.1 “TempFail”)
So is it a “TempFail” and will continue to try to deliver it, or is it a “permanent fatal error”???
this has been going on all year that I have not been getting some e-mails… I sent myself to my aol account an e-mail from my gmail two hrs ago and have still not gotten it… I have been
with aol since the 90s and people have been telling me to move… maybe I should because
I can’t do business this way…
EXACTLY what Martin said. I’ve been with AOL since 1995 or so. But I can’t stand it when people ask me about emails they sent hours ago that I haven’t received.
I am having the same issue. Yesterday, it took about 7 hours for me to finally receive my emails….and they were of an important nature. What is going on with AOL? I have been with AOL forever and all of my clients have my AOL email address which is my reason for staying with AOL (even though I have Comcast service at my home and a Comcast email address).
I have also noticed a heavy impact on our email campaigns performance lately. A heavy percentage of valid confirmed opt-in contacts are soft-bouncing:
—————————
Delivery temporarily suspended: host mailin-04.mx.aol.com[64.12.138.161] refused to talk to me: 421 mtain-mp06.r1000.mx.aol.com Service unavailable – try again later–
—————————
Even though we are part of the feedback loop, and are on their whitelist, the delivery rate has dropped significantly. I hope AOL can address this soon!
I’ve seen the 521 5.2.1 “TempFail” as well. Seeing them as recentlly as 10/15.
Here is one I just saw on Wednesday trying to email my attorney critical documents. I received the test email from them just fine. When I replied to that email, I got:
Unexpected connection response from server:
421 mtain-dg04.r1000.mx.aol.com Service unavailable – try again later
This is not the first time I have had problems trying to email him.
I’m quite concerned. I have experienced the following:
Important mail being bounced back to the sender
Some mail never arriving
Mails I have seen and opened, vanishing
Not being able to find things when using accurate search terms -eg word “Jane” in search term – doesn’t find it, but I find it after manual search
Very poor spellcheck suggestions and sometimes none where there should be one
Yeah ,I wrote a mail to a guy who’s got an ‘aol’ adress.
I received an error message (I use an ‘@orange.fr’ adress).
Does the problem come from aol?
AOL mail has been a nightmare for 3 – 4 days now
“technical problem”, again and again.
using Google Chrome seems to aggravate it.
IE has less problems.
(Axoul, no; you just have an old address or the person is a spammer)