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The server returned status code 550 - Mailbox unavailable. The server response was: Requested action not taken: mailbox unavailable RRS feed

  • Question

  • Hi,

    Until recently, mailflow has been perfectly fine for all mailboxes across both our domains. However, I've just noticed that mail to the domain farnley.leeds.sch.uk from external sources is no longer working.

    I can send mail out from a farnley.leeds.sch.uk mailbox, but can't get a response back.

    All internal mail works fine. I've got a feeling this is going to be something simple, but I'm kicking myself trying to find where the problem is.

    Here are my results from the remote analyser:

    Testing inbound SMTP mail flow for domain year9@farnley.leeds.sch.uk.
      ExRCA failed to test inbound SMTP mail flow.
     
    Test Steps
     
    Attempting to retrieve DNS MX records for domain farnley.leeds.sch.uk.
      One or more MX records were successfully retrieved from DNS.
     
    Additional Details
      MX Records Host smtp.morley.leeds.sch.uk, Preference 10
    Testing Mail Exchanger smtp.morley.leeds.sch.uk.
      One or more SMTP tests failed for this Mail Exchanger.
     
    Test Steps
     
    Attempting to resolve the host name smtp.morley.leeds.sch.uk in DNS.
      The host name resolved successfully.
     
    Additional Details
      IP addresses returned: 87.82.212.213
    Testing TCP port 25 on host smtp.morley.leeds.sch.uk to ensure it's listening and open.
      The port was opened successfully.
     
    Additional Details
      Banner received: 220 smtp.morley.leeds.sch.uk ESMTP Service ready
    Attempting to send a test e-mail message to year9@farnley.leeds.sch.uk using MX smtp.morley.leeds.sch.uk.
      Delivery of the test message failed.
     
    Additional Details
      The server returned status code 550 - Mailbox unavailable. The server response was: Requested action not taken: mailbox unavailable


    Thursday, February 9, 2012 11:58 AM

Answers

  • SOLVED:

    Turns out it was our watchguard firewall that was the problem. The SMTP inbound rule had stopped working for reasons yet unknown. Adding in the accepted domain again fixed the problem.

    Thursday, February 9, 2012 1:17 PM

All replies

  • Hi,

    And you do have a mailbox with the address year9@farnley.leeds.sch.uk ?

    Leif

    Thursday, February 9, 2012 12:05 PM
  •  Yeah, that mailbox has been in use for a while. It has mail items sat in the inbox from a week back, plus sent items as well. The mailbox has worked perfectly fine before, along with about 30 others. Suddenly external mail to this domain has stopped working, and I have no idea why.
    Thursday, February 9, 2012 12:12 PM
  • 550 responses typically mean either the users mailbox was unavailable at the time the message delivery was attempted or the mailbox doesn't exist. Try sending the message to the recipient again and see if you get a 550 error. If you receive a 550 message the second time then I would double check with the recipient to make certain that particular mailbox is still active and go from there. can you check that particular mail through owa http://social.technet.microsoft.com/Forums/sk/exchange2010/thread/935846c8-43ab-4407-870a-ac485d2ed58d http://forums.asp.net/t/1093363.aspx/1
    Thursday, February 9, 2012 12:26 PM
  • 550 responses typically mean either the users mailbox was unavailable at the time the message delivery was attempted or the mailbox doesn't exist. Try sending the message to the recipient again and see if you get a 550 error. If you receive a 550 message the second time then I would double check with the recipient to make certain that particular mailbox is still active and go from there. can you check that particular mail through owa http://social.technet.microsoft.com/Forums/sk/exchange2010/thread/935846c8-43ab-4407-870a-ac485d2ed58d http://forums.asp.net/t/1093363.aspx/1
    I'm currently logged into the mailbox now in OWA. I've sent about 10 external mails to this account, all with the same bounce back. I can send external mail whilst logged into the OWA, and I can send and receive internal mail.
    Thursday, February 9, 2012 12:31 PM
  • SOLVED:

    Turns out it was our watchguard firewall that was the problem. The SMTP inbound rule had stopped working for reasons yet unknown. Adding in the accepted domain again fixed the problem.

    Thursday, February 9, 2012 1:17 PM