Requested #550 Requested action not taken: mailbox unavailable ## RRS feed

  • Question

  • I am working as system administrator at Preferred Engineering Pvt Ltd. We are using physical Exchange Server 2008R2/2007 exchange. When we send an email to a specific domain like Hotmail, Outlook or Live, we are getting error #550 mailbox is unavailable. Forex. : Requested #550 Requested action not taken: mailbox unavailable ## . But we can receive emails from that domain. Other emails traffic going smooth. 


    Gaurav Bankar

    Saturday, July 8, 2017 5:17 AM

All replies

  • Do you have a send connector for Internet mail, i.e., one with the AddressSpaces parameter set to "*"?

    Ed Crowley MVP "There are seldom good technological solutions to behavioral problems."
    Celebrating 20 years of providing Exchange peer support!

    Saturday, July 8, 2017 4:21 PM
  • Hi,

    Thanks for contacting our forum.

    Does this issue affect all the emails to external domains? Firstly we should create a send connector for emails to internet as Ed mentioned above.

    Please post out all the detailed error message of the NDR message when you send a message.

    And also the information of your send connectors with the command: get-sendconnector | fl

    We can collect the SMTP log and see if any detailed error messages for troubleshooting as below steps:

    1) Run following command to enable protocol log: 

    Get-sendconnector | Set-sendconnector -protocollogginglevel verbose     

    2) Do some tests to send to those domains,

    3) Collect the latest SMTP logs from following location on your hub server: 

    C:\Program Files\Microsoft\Exchange Server\TransportRoles\Logs\ProtocolLog\SmtpSend 

    Meanwhile, please post out the log of test messages.

    Hope it helps and thanks for your effort.


    Jason Chao

    Please remember to mark the replies as answers if they help.
    If you have feedback for TechNet Subscriber Support, contact tnmff@microsoft.com.

    Monday, July 10, 2017 8:05 AM