XFOR: Non-Delivery Report: Unknown Or Illegal User (193924)


The information in this article applies to:

  • Microsoft Exchange Server 5.0
  • Microsoft Exchange Server 5.5
This article was previously published under Q193924

SYMPTOMS

When sending a message to a Simple Mail Transfer Protocol (SMTP) address, users and administrators of Microsoft Exchange may receive a non-delivery report (NDR) similar to the following: 
   From:   System Administrator
   Sent:   Wednesday, March 11, 1998 8:22 AM
   To:   Test User:Dekort, Ed
   Subject:   Undeliverable: Test Message

   Your message did not reach some or all of the intended recipients.

      Subject:   Test Message
      Sent:   03/11/1998 8:21 AM

   The following recipient(s) could not be reached:

      Testing UpJohn:Dekort, Ed on 03/11/1998 8:22 AM
      The recipient name is not recognized
      MSEXCH:IMC:SciCor:SciCorUS:HAWK 3553 553 5.1.1 unknown or illegal
      user: my.user.company.com

CAUSE

The SMTP address declared is not a fully qualified SMTP address.

In the example used, the SMTP address, my.user.company.com, was probably intended to read my.user@company.com.
Modification Type:MinorLast Reviewed:4/28/2005
Keywords:kbprb KB193924
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