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550 5.1.1 User unknown

    Question

  • Hello,
    I have received "550 5.1.1 User unknown" error when I send mail from external mail (such as gmail) to my one of users. (user1@contoso.com)

    This problem exists only in one user. Everything is okay with other users.

    After uncheck "Block messages sent to recipients that do not exist in the directory" on Recipient Filtering on the "Edge Transport Server" my problem is solved.

    My Question is:
    if the user (user1@contoso.com) exists in my AD then why I received "550 5.1.1 User unknown" error?
    Why I should uncheck "Block messages sent to recipients that do not exist in the directory"?
    I don't want to uncheck that settings.

    My Environment:

    Two Mailbox Server (Exchange 2013 CU13);

    One Edge Transport Server (Exchange Server 2010);

    I have installed Anti-spam and anti-malware on Mailbox servers.

    Thank you for your help...


    • Edited by Turgut Valiyev Thursday, December 29, 2016 10:05 AM be made more exact
    Thursday, December 29, 2016 9:59 AM

All replies

  • Hi,

    please check Edge server synchronization:
    Test-EdgeSynchronization -VerifyRecipient user1@contoso.com

    Thursday, December 29, 2016 11:33 AM
  • Hi,

    When we enable the blocking of messages sent to recipients who don't exist in the Exchange organization, the blocking list of specific recipients was configured by the Set-RecipientFilterConfig cmdlet. So what have you configured by the cmdlet on Edge Server?

    Get-RecipientFilterConfig

    https://technet.microsoft.com/en-us/library/bb125187(v=exchg.160).aspx


    Best Regards,

    Lynn-Li
    TechNet Community Support


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

    Friday, December 30, 2016 2:04 AM
    Moderator
  • Hi, Turgut Valiyev

    Are the suggestions above helpful for you? If you have any further problems, feel free to let me know.


    Best Regards,

    Lynn-Li
    TechNet Community Support


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

    Tuesday, January 3, 2017 1:51 AM
    Moderator