Exchange 2010 : #550 4.4.7 QUEUE.Expired; message expired ##

Last week I had a customer who started having problems sending emails to one particular recipient.

The user was getting bounce mails with the error

> #550 4.4.7 QUEUE.Expired; message expired ##

Which typically would mean that the sending server has given up.

Protocol-logs show that the server initiates a connection, but that’s it, no further logging. It never gets as far as trying to send an email.

The queue says the error message is Helo command rejected: Host not found.

Which would suggest that the receiving server doesn’t accept the HELO/EHLO command, because it’s running a reverse lookup to verify senders identity.


Now, why is it doing this? Because a pretty basic setting has been skipped.

Under the servers send connector, this field was blank:






Which means it didn’t identify itself properly. Set it as the servers external address and thar she blew!

8 thoughts on “Exchange 2010 : #550 4.4.7 QUEUE.Expired; message expired ##

  1. Efrain

    It NOT work for me, I filled out this field when I first created, and Im still unable to send or receive mails

    My scenario:
    Router Public IP= (Comcast)
    DNS already in placed, MX Already in placed, A record already in placed

    What im missed?


    1. Kristoffer Post author

      Well, does the address you send from ( resolve to the fqdn you filled in? You’re not using a different external address, or routing it through a spamfilter?

  2. bobby

    I have followed ur post..its very nice…Im getting error message while sending an email from exchange outlook 2010 to sharepoint2010 server….after two days failure notice is cuming…pls resolve my issue. Thanks in Advance

    1. Kristoffer Post author

      I’m guessing it’s a completely different problem in your case. Are you sure the address you are sending to is resolvable from the Exchange server?

  3. Allen L

    Another good reason is your DNS, or Root Hints cannot resolve, or find the MX record. Try changing the DNS forwarders in your DNS /Active Directory server.


Leave a Reply

Your email address will not be published. Required fields are marked *