Question : 5.7.1 NDR Error Messages after Exchange new build

I have built a new domain but some of my users are now getting 5.7.1 NDR errors. They are getting the following back as undeliverable.

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

      Subject: WHATEVER
      Sent:      18/12/2006 17:16

The following recipient(s) could not be reached:

      Lee *****(*****@***.com) on 18/12/2006 17:16
            You do not have permission to send to this recipient.  For assistance, contact your system administrator.
            MSEXCH:MSExchangeIS:/DC=LOCAL/DC=CMRGROUP:CMREX1

I have applied the SP3 to Exchange but still getting these errors. I am using Exchange 2000 on a Win 2k server OS and Outlook 2003 at the users end.

Answer : 5.7.1 NDR Error Messages after Exchange new build

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