I am wondering why do I receive the following message for some email attempts

**Delivery is delayed to these recipients or groups:

This message hasn't been delivered yet. Delivery will continue to be attempted.

The server will keep trying to deliver this message for the next 1 days, 19 hours and 57 minutes. You'll be notified if the message can't be delivered by that time.**


  • Have you done any fault finding? Are you an end user or administrator?
    – Zapto
    Feb 24, 2012 at 9:25
  • This was reported to me from a user inside our network. We have just installed SBS 2011 and Exchange 2010.
    – John
    Feb 24, 2012 at 10:25
  • Can you let us know what seteps that you have taken to resolve this and provide some facts about what is going on. This quesion is very opened ended without some more detail.
    – Zapto
    Feb 24, 2012 at 10:28
  • If I knew how to resolve it, or where to start looking, I would not be here asking for help. I don't know what causes delay. Where should I start looking? Sender receives this message, and recipient does not receive the email. Message was sent from OWA.
    – John
    Feb 24, 2012 at 11:25
  • What confuses me is that there can be various reasons for this message, such as - routing error at your ISP or the recipients ISP - the receiving server is rejecting the message - the receiving server is not alive - the receiving server cannot be connected. All of that is wrapped up in message Delivery is delayed to these recipients or groups: Is there an option to configure Exchange for sender to receive a more detailed message. Where can I access Exchange 2010 message log?
    – John
    Feb 24, 2012 at 11:30

1 Answer 1


There are a few things needed to troubleshoot these kinds of errors, though knowing how they're generated is the first step. This error is a very, very standard error for SMTP mailers of all types; it's the delivery delay notice given when the first few attempts to send mail to a mailer fail (generally for connectivity reasons, though others like 'mailbox full' can also cause this). If a mail is rejected for a specific reason, such as an SMTP-550-Not-Allowed error that generates a different message. But for "the destination mailer isn't talking", this is the message that gets generated.

Knowing that, you can take the message that generated the delay message and look at the To: line. That will tell you what mailer your Exchange system can't contact.

If the To: is an internal user, you have a problem inside Exchange. I'm not sure if SBS has it, but hunt up the Message Tracking tool and try to see how that message got routed.

If the To: is an external user, but not all external mail fails, then you need to investigate why your Exchange server can't talk to that domain. The techniques for this vary, depending on the exact failure. Again, I'm not sure if SBS has this option but you can turn on 'protocol level logging' which will provide detailed logs for every SMTP transaction (this gets very, very spammy); clues may hide within.

If the To: is an external user, and all external mail fails this way, then you need to look into your Exchange external-connector settings since that's probably where the problem is.

  • 2
    +1. EXCEPT: if that is an external user, ignore the error and come back tomorrow. See, people take down their email servers. Shit happens. That just means delayed. If it is still delayed a day later - another message basically - THEN you investigate. I wont spend admin time just because custoemr X decided that today he updates his server and takes 2-3 hours to do so.
    – TomTom
    Feb 24, 2012 at 11:49
  • @TomTOm HAH. Yes. The 'sit on the request for 4 hours and ask if it's still a problem' method works quite well for email delivery problems. Email is not IM.
    – sysadmin1138
    Feb 24, 2012 at 11:55
  • 1
    Tell that users getting upset if you dont answer in 5 minutes ;) All that message says is "ok, there is a delay here, please dont expect the other person to reply yet" ;)
    – TomTom
    Feb 24, 2012 at 11:58
  • Great response, thank you. Since we just moved to Exchange 2010 and only 4 messages sent within an hour failed (sent from remote location via OWA), I figured out there is a problem with Exchange. All recipients (to) were external users, but it was suspicious that only those 4 messaged failed. Routing issue?
    – John
    Feb 24, 2012 at 11:58
  • @John If it's within a short period of time, all the delivery status messages may not have been sent yet. Though, if only a few of a bunch of external-destined messages have failed it does suggest a few things. Verify the DNS resolver on your SBS server does yield MX records for the destination domains. Next turn on protocol level logging and see what happens when it tries to talk to those mailers, there may be interesting messages. Your server may be 'gray-listed' for some reason.
    – sysadmin1138
    Feb 24, 2012 at 12:05

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