420 4.2.0 RESOLVER.ADR.Ambiguous; ambiguous address

Posted on 2011-04-27
Last Modified: 2012-05-11
We  are in the middle of a migration from Exchange 2003 to Exchange 2010.  I see there that there are over 100 items in the submission queue for Exchange 2010.  All of the items are from the same address ( to the same recipient address (  All of the messages have the same error:

Identity: CAS01\Submission\257062
Subject: Folder Content
Internet Message ID: <>
From Address:
Status: Retry
Size (KB): 42
Message Source Name: SMTP:Default CAS01
Source IP: x.x.x.x
SCL: -1
Date Received: 4/25/2011 4:03:09 PM
Expiration Time: 4/27/2011 4:03:09 PM
Last Error: 420 4.2.0 RESOLVER.ADR.Ambiguous; ambiguous address
Queue ID: CAS01\Submission

I went through the following links:

When I do an LDAP search for the email recipient address ( it doesn't come up in the search.  I confirmed my syntax was correct by finding an account that I know does exist.

I did find SMTP addresses on the System mailboxes in the storage groups of the Exchange 2003 server that had similar addresses like  &, so I'm wondering if the address is a remnant.

Any help would be appreciated.

Question by:sillz
    LVL 25

    Expert Comment

    Slightly different number in the error, but the remainder of the code is the same (ambiguous address) plus just gone through a migration:
    LVL 25

    Expert Comment


    Author Comment

    I saw those docs too.  I tried searching for the recipient address, but it doesn't seem to exist as a user or contact.

    Accepted Solution

    We found the duplicate using the query in my original posting.  We just needed to make sure that we were searching across multiple domains

    Author Closing Comment

    we juts needed to search across our multiple domains

    Author Comment

    We resolved our own problem by running the query in my original posting.  We had to run the query in multiple domains to find the duplicates.  

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