Mail problems at AOL

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 []: 521 5.2.1 :(CON:B1) reported by the owner of a low volume discussion list with paying subscribers that should have zero complaints.

delivery temporarily suspended: host[] refused to talk to me: 421 Service unavailable – try again later reported by all sorts of senders. failed after I sent the message. Remote host said: 521 5.2.1 “TempFail” reported by a small mail host.

554 ESMTP not accepting connections reported by an ESP.

421 4.7.0 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.


  1. Marcel says

    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.

    1. laura says

      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: There was also a round of problems back in May:

      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.

  2. Andrew Edelstein says

    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 ( while connected from ( to (

    This is the same thing that happened to us during the other dates Laura mentions.

  3. Bob Curtis says

    I wish they could even get their error messages straight:
    —– The following addresses had permanent fatal errors —–
    (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”???

  4. martin says

    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…

  5. Lowell says

    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.

  6. Myrna Malkin says

    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).

  7. Richard Vohsing says

    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[] refused to talk to me: 421 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!

  8. Brian says

    I’ve seen the 521 5.2.1 “TempFail” as well. Seeing them as recentlly as 10/15.

  9. Tim says

    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 Service unavailable – try again later

    This is not the first time I have had problems trying to email him.

  10. Cheryl says

    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

  11. Axoul says

    Yeah ,I wrote a mail to a guy who’s got an ‘aol’ adress.
    I received an error message (I use an ‘’ adress).
    Does the problem come from aol?

  12. Tim says

    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)

  13. David says

    Can I join the band of folk complaining about AOL. I am finding people not able to send to it or very long delays in me receiving replies that had been sent… and it am paying for AOL

  14. Nick Shaw says

    I am consistently only able to occasionally receive emails sent from an address a few miles away

    Linda gets no undelivered bounce back.

    Please explain and rectify

    1. laura says

      Nick, this is not a question I can answer. You will need to contact AOL support.

  15. Brian F Colin says

    As of yesterday, EVERYTHING send from my aol account goes into my friends & coworkers SPAM folders, or is not delivered at all!

    Some co-workers tell me that the emails are missing a “Signed by MX.AOL.COM” signature…

    What does that mean &/or how can I change it.

    1. laura says

      You should really talk to AOL support about this.

  16. Sandra says


    I know where some of ur msg are going and that is to my email inbox. I can not open them, but they r all AOL.
    I want this stopped
    This started about 5 days ago and as I delete 12 msg, I get 12 back. I think if I kept deleting I would get flooded with msg.
    I dont have any connections with AOL
    I too am frustrated,
    What can I do?

  17. Andrew says

    Verifying if there are still issues. We are unable to send to an AOL account – receiving the error message: ( ESMTP not accepting connections)

    This thread is from 2012….is this seriously still an issue?

    1. laura says

      It is a recurring problem. It’s not constant.

  18. Rob R. says

    Hey @Andrew,

    I am having the same problem:

    Action: delayed
    Status: 4.0.0
    Remote-MTA: dns;
    Diagnostic-Code: smtp; 554 ESMTP not accepting connections

    I was shocked to find this thread and even more so that it is from 2012.

  19. Andrew Homsky says

    Good Evening

    AOL emails for some reason get marked as “FAILED” with the following message:

    IPADDR failed after I sent the message./Remote host said: 521 5.2.1 : AOL will not accept delivery of this message./

    We are email marketing firm and we do not send SPAM.

    I contacted customer care and submitted numerous forms – but no response and we are still facing the same daily.

    Any advice?

    Thank you very much
    Andrew Homsky

    1. laura says

      That’s not a full AOL bounce message, so the first step is to get the full rejection message from AOL. Once you have that, it will give you an idea if it’s a content problem or an IP reputation problem or something else. Once you know what is triggering the filter, then you can modify your processes.

  20. David says

    AOL made all their money in the early 1990’s charging by the minute. While they wait for another company to buy them out the service gets worse and worse. Every other email I try to send gives me an error message. It just started within the last two weeks. Do they go directly to NSA first before I am allowed to send them?

  21. Dream Fighter says

    Still issues at AOL. I wish my customers didn’t have their email accounts with AOL! Such a headache!
    SMTP error from remote mail server after initial connection:
    host []: 554 ESMTP not accepting connections

  22. Elaine says

    I am so upset……it has been months since I have been able to send emails out from my aol account. When I call aol to advise them of my problem they try to sell me something. When I try to send a message out I get: Technical issues encountered or something to that effect. Does anyone know how to resolve this ????? If so ……respond to Thanks

  23. Ken says

    Hello Laura,

    Please can advise. We see alot of these AOL errors
    SMTP service unavailable: “421 Service unavailable – try again later” received from ( while connected from ( to (
    SMTP service unavailable: “421 4.7.1 : (DYN:T1)” received from ( while connected from ( to (

    I’ve sent a couple of messages to AOL requesting for help. As always, nothing has been done.

    Can Laura or any one here help please?

    1. laura says

      If that’s a mail server that you use, then there’s some bad mail going through it that is triggering AOL’s filters. Right now, these are temporary blocks but if there is no improvement in your mail, then it’s likely that you will see more permanent blocks and worse delivery over time.

      We can help you identify the underlying cause of your issues and provide consulting to resolve them. Feel free to contact us by phone or our contact address for more information.

  24. Markus Dietrich says

    hi – i receive for several times this :>: delivery temporarily suspended: host[] refused to talk to me: 554 5.7.1 :

    can you explain why it happened ?

    how can i solve the problem ?


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