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Why Am I Getting a “Delivery Status Notification (Delay)” on an Email I Sent?

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I am trying to send an e-mail to a co-worker and I keep getting the following message:

Delivery Status Notification (Delay)
 This is an automatically generated Delivery Status Notification.
 THIS IS A WARNING MESSAGE ONLY.
 YOU DO NOT NEED TO RESEND YOUR MESSAGE.
 Delivery to the following recipients has been delayed.

The strange thing is that it is only happening with that specific email address. What does it mean, and why it is happening?

It means exactly what it says: the email you sent hasn’t been delivered yet; it’s been delayed.

The mail system will continue to attempt to deliver the email. Eventually, it’ll either be delivered, or you’ll get a fatal-error message.

Why? Because.

Seriously, there are many, many reasons that email could be delayed.

And if that’s a problem for you, then you may be thinking about email the wrong way.

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Real time was never intended

One thing many people fail to realize is that email was never meant to be “real time”.

The entire email infrastructure is actually built to expect (and properly handle) delays ranging from a few minutes to hours to even days. While most of the time, email arrives nearly instantaneously, the fact is, you can’t count on it.

Email is what’s called a “store and forward” system. When you send an email, it’s received by a mail server, stored for some period of time, and then forwarded to the next server in the path to get your email to your recipient. Finally it lands on your recipient’s mail server, where it’s stored until the recipient downloads it (another kind of “forward” to their inbox) or reads it online.

Those “periods of time” that a server might hold on to your message before forwarding it are typically very short, but there’s really no guarantee that they will be. There could easily be any number of legitimate mail server delays along the path that your email takes to get to your recipient.

That’s not the system being broken; that’s how the system works.

Email Delayed

Resilience is built into the email system

It’s important to remember that the internet – the system, computers, and connections between them – wasn’t always as generally reliable as it is today. Servers could be down for periods of time, and the connections between them could fail, or weren’t even continuous connections at all.

The email system we still use today was built to handle all that instability gracefully and still get your email through.

That means that today, when, for example, your recipient’s mail server is temporarily off-line, the email system just deals with it.

Rather than not deliver the email, your mail server keeps trying to pass the message along. In some cases, it’s nice enough to let you know that this is happening, by sending you the “Delivery Status Notification (Delay)” message.

Eventually, when the recipient’s mail server comes back online, the delivery succeeds.

Failure remains an option

Of course, a sending server will only try for so long. If I recall correctly, if the message cannot be delivered after five days, you’ll get an error message – a “bounce” message that indicates a failure. Instead of a warning telling you that the mail was delayed, it’ll tell you that try as it might, the message didn’t make it through.

There are many reasons mail can be delayed. I see it most often when mail servers themselves are overloaded, unstable, or when they have problems with their connectivity to the internet.

The most common reason? You sent it to the wrong email address – a typo, perhaps.

If you get this “Delivery Status Notification (Delay)” warning, there’s nothing you can really do, other than to make sure you sent it to the correct address.

If your message is truly urgent, you may need to find a way other than email to make contact.

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20 comments on “Why Am I Getting a “Delivery Status Notification (Delay)” on an Email I Sent?”

  1. Hi, I have recently been told my people trying to email the above address that it either comes up with a “Delivery Status Notification (Delay)” or “Unable to deliver message to the following recipients, due to being unable to connect successfully to the destination mail server” Delivery Status Notification (Failure). What can I do about this as this has only recently started & I have been using the account for over 5 years with no problems.
    The only thing I have done is started to use Norton internet security 2007
    Please advise. Thanks in advance Shiraz

  2. I understand the reasons for delayed messages..sort of. But, why do I get on-time e-mails from some people and accounts while other people are getting a delayed message prompt for messages sent to me and I don’t get their e-mail?

  3. My emails are being delayed also. I am using hotmail, is there any what that I can go and just pull those emails so that they just don’t deliver at all?

  4. It’s not entirely true that there is “nothing you can do”. If you are on a local network sending out emails or going through a local doman, MS has a good KB article on the subject and how to resolve it by adjusting settings on the SMTP server:

    http://support.microsoft.com/kb/329636

    This may help some of you with this issue.

    Oh, that’s going to apply to about 1/100th of 1% of my readers. First step is to “Open Exchange System Manager.” – something most people have never heard of, don’t use or have no access to. Great for the rest though Smile.

    Leo
    22-Jan-2011

  5. Well i understand that i cant do anything, but the message i sent was an important one, how do i know when it will send, if not ever? its pretty annoying.

    If you get a delay message you should eventually get a failure message if it’s unable to send. The delay can be days, however.

    Leo
    28-Jun-2011

  6. I get a “WARNING. Mail Delayed: from “MAILER-DAEMON@server115.appriver.com” several times a day. This has been going on for at least 1 month. How do I make is stop. Can I spam out the from address without losing other emails? When is looked up that server I get info on an email address extractor from text.

  7. I’ve noticed that this only happens when I send an MS Outlook meeting update to the invitees. The original meeting invite gets sent and received fine. But if I change the date or time of the meeting, I get the “Delay” message. I’m using SBS2003 w/Exchange server and MS Outlook 2007.

  8. Can a email that has been sent hijacked an its attachments edited before getting to its destination?

    Theoretically possible, but I’ve never ever heard of it actually being done.

    Leo
    25-Sep-2012
  9. I`ve got such message from postmaster@mail.hotmail.com…..
    what actually does it mean ?

    “This is an automatically generated Delivery Status Notification.
    THIS IS A WARNING MESSAGE ONLY.
    YOU DO NOT NEED TO RESEND YOUR MESSAGE.
    Delivery to the following recipients has been delayed.
    {email address removed}”

    • I can’t find the email to resend it. Where is it now? It’s not in the send file or the draft file. I know there is an error in the address; that’s why it won’t go through.

  10. Can i cancel this mail ? i sent an important email with an error in it, i whish i could seize the delay thing and cancel it .. can i ?

  11. Why would I get a Hotmail rejection notice for an Outlook account? {email address removed}@hotmail.com
    9:52 AM (22 hours ago)

    to me
    This is an automatically generated Delivery Status Notification.
    Delivery to the following recipients failed.
    {email address removed}@outlook.com

    Final-Recipient: rfc822;{email address removed}@outlook.com
    Action: failed
    Status: 5.5.0
    Diagnostic-Code: smtp;550 Requested action not taken: mailbox unavailable (-854855861:4278:-2147467259)

    • Because of the very reason included in the message: the mailbox you’re trying to send to is unavailable. (That can mean many different things from a bad email address to problems with the recipient’s email account to other issues.)

      (Oh, and Hotmail and Outlook.com and msn.com and live.com and more are all just Microsoft email so they’re all really the same thing.

  12. If I get the error message just below:

    Delivery Status Notification (Delay)
    This is an automatically generated Delivery Status Notification.
    THIS IS A WARNING MESSAGE ONLY.
    YOU DO NOT NEED TO RESEND YOUR MESSAGE.
    Delivery to the following recipients has been delayed

    May the email go through if I send it from a different email address? Hotmail vs Gmail, for example.

    • Although the recommendation is to wait for the email to go through, whenever I get that warning, I send the email again from the same account (if you prefer to try a different account, that should also work), and the email goes through instantaneously. Then after a few days a message usually comes saying the original email failed to send.

  13. I can actually remember back in the early 1990’s I had a WWIV BBS that would dial in via modem every so often to the main system that had a T-1 line and send/receive the messages waiting in the spool! Cool times! I was always fascinated by it. So you are right, there was a time when everything was not fullly interconnected 24/7.

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