AOL bounces and false positives

A number of people have been seeing an increase in AOL bounces over the last few days. Some of these are the new rejection 554/421 CON:B1 message. This is, basically, you’ve topped our thresholds, back off.

The other one is a bit more interesting. The error message a lot of people are seeing is 554/421 RLY:SN. Senders should only be getting this error message when they are sending email from a banned address.

This error indicates you are sending email using a disallowed AOL.COM screenname as your FROM or REPLY-TO address, or as one of AOL’s affiliates from an unauthorized IP address. Example:

Clearly this is AOL attempting to minimize phishing and spoofing of the AOL brand. This is a great thing.

Unfortunately, there seems to be some problems with the current implementation. This rule is catching perfectly legitimate email. One report I have seen is that mail with in the from address is getting rejected with this message. That means all those small businesses sending mail from their addresses through an ESP are seeing problems. Another report I’ve seen is that email addresses with “a” “o” “l” in order (like, for instance, are also getting rejections.

It’s very possible that this filter is catching other mail, too.

Folks I’ve talked to are in touch with AOL and AOL is working on fixing the issue.

Note these do seem to be intermittent errors and not every email with an address in the from line or some rendition of “aol” in the email address is getting bounced. But if you do start seeing increases in the number of AOL bounces and they are RLY:SN, this may be why. A short term work around will probably be to modify From: addresses where possible. Longer term, we’re just going to have to wait for AOL to fix things.


  1. Jessica McMillan says

    Hey, we have been seeing a huge increase in 554-CON:B1 bounces to the point where only 1 in 3 emails delivers.

    What kind of things can we do to rebuild traction on these tarnished IP’s getting the CON B1’s? Specifically, what do you mean “you’ve topped our thresholds, back off.”

    Does that mean send less, or send zero emails for a period of time? We are currently trying things to help and so far sending less doesn’t seem to help alot. Could not sending the daily newsletter for a couple/few days help?

  2. CON:B1 says

    Well, it’s like thresholds are paper Dixie cups. What it means is that you’ve poured too much whine and now you have to let aol drink some.

  3. The Other Barry says

    The sharp increase in CON:B1 errors specifically to low volume IPs without much of a reputation is “something broken”. Supposedly they’re working on it, but it’s been days and no fix yet.

  4. Jessica McMillan says

    It feels like our reputation is getting worse. It is clearly visible in the sent:bounce:open:click metrics. We are sending limited amounts compared to what we were before this sharp increase in CONB1’s. Complaints are low–lower than 1 in 1000 (and even less now due to lower amounts landing in the inbox).

    From what I understand, this dixie cup analogy means we need to stop sending and allow AOL to parse results?

    We’ve seen conditions go sharply bad almost to the minute on the 1st of this month. Thats why I would agree that it’s an AOL originated issue. Something with their filtering techniques seemed to change around August 1st.

    Has anyone seen similar events where things have gotten worse around August 1? and specifically has anyone been able to develop any positive solution that achieves less CON:B1’s?

  5. Karl Henselin says

    I am still hoping too. Many of my users are att subscribers, and I have been getting most of my messages bounced as well. I found that my SPF record had been duplicated and the first one was wrong, so hopefully that will be part of if not all of my problem. If it is, perhaps you should check yours too. If not, let me know if you find a solution. Thanks.

  6. Nita says

    My AOL mail is rejected by Verizon – because: Network connection timed out.
    It says the network issue will be resolved. Try waiting a bit and then try resending your message. If that does not work, consider contacting your recipients through an alternate means. Send/receive log is attached. More information about 5.4.2 delivery errors are available if you want or need it. The outbound connection was established, but was unable to complete the message transaction, either because of time-out, or inadequate connection quality. This is useful only as a persistent transient error. – See more at:×250#sthash.Avia9ZIV.dpuf

    The outbound connection was established, but was unable to complete the message transaction, either because of time-out, or inadequate connection quality. This is useful only as a persistent transient error. – See more at:×250#sthash.Avia9ZIV.dpuf


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