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Exchange rejects mail to all users if just one recipient is wrong RRS feed

  • Question

  • Hello,

    After upgrading to Exchange 2013 from 2010, it seems that if an external sender sends an email to several of our internal users and gets just one of the addresses wrong.  It will reject the message and give #5.1.1 SMTP; 550 5.1.1 User unknown> #SMTP#  for each recipient - not just the one wrong address.

    The e-mail address you entered couldn't be found. Please check the recipient's e-mail address and try to resend the message. If the problem continues, please contact your helpdesk.

    #5.1.1 SMTP; 550 5.1.1 User unknown> #SMTP#<u5:p></u5:p>

    None of the legitimate users actually receive anything.

    This is quite confusing for the sender, as they don't realise that they got just one address wrong, they think there is a problem with our mail server (which there kind of is).

    We have Exchange 2013 CU3 installed on a single Windows 2012 server.  CodeTwo Exchange rules 2013 are also installed for outgoing signatures, but I believe this problem has been happening before we added that.

    Any help is appreciated.

    Cheers

    Tom

    Sunday, January 26, 2014 7:52 PM

Answers

All replies

  • Look like this is Recipient Filtering, following KB will give you the answer,

    http://technet.microsoft.com/en-us/library/bb123891%28v=exchg.150%29.aspx

    tnx


    Lrok

    Monday, January 27, 2014 12:17 AM
  • Hi Tom,

    Does this issue occur in OWA?

    Please using OWA for testing.

    If it is normal in OWA, it seems like an issue on the Outlook Client side.

    Please trying to run Outlook under safe mode to avoid some AVs, add-ins and firewall.

    Please trying to re-create a new profile to refresh the caches.

     

    Feel free to contact me if there is any problem.

     

    Thanks

    Mavis


    Mavis Huang
    TechNet Community Support

    Tuesday, January 28, 2014 3:11 AM
  • Hi Tom,

    Any update?

     

    Thanks

    Mavis


    Mavis Huang
    TechNet Community Support

    Tuesday, February 4, 2014 9:14 AM
  • Apologies everyone, I was expecting this forum to alert me when people replied to this thread, but it didn't, then I got busy with other things.

    Anyway, the problem got raised again and I can confirm it is recipient filtering that causes the problem.  If you turn it off, then it just sends the NDR for the one bad mailbox.  When it is on, it rejects the email to all the recipients. Seems like very unhelpful behavior.

    Set-RecipientFilterConfig -Enabled $false does the trick.  Just means that the mail gets rejected on the HT role rather than the edge.  We don't have an edge server anyway!

    Thanks Lrok!

    Cheers

    Tom


    Monday, July 7, 2014 9:29 PM