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Article ID: 243626 - Last Review: October 22, 2013 - Revision: 5.2

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During normal operation, the following event may appear in the application event log:
Event ID: 2006
Source: MSExchangeIS Private
Category: Transport Sending
Description: The generation of a delivery report or a non-delivery report has failed due to error 0xfffff9bf.


Delivery receipts (DRs) are not being properly routed to the message transfer agent (MTA) for delivery when delegates and recipients exist on different servers. See the "More Information" section for exact steps to reproduce this issue.


To resolve this problem, obtain the latest service pack for Exchange Server 5.5. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:
191014  ( ) XGEN: How to Obtain the latest Exchange Server 5.5 Service Pack
The following files are available for download from the Microsoft Download Center:
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Download Q248838engi.exe now (
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Download Q248838enga.exe now (
For additional information about how to download Microsoft Support files, click the following article number to view the article in the Microsoft Knowledge Base:
119591  ( ) How to Obtain Microsoft Support Files from Online Services
Microsoft scanned this file for viruses. Microsoft used the most current virus-detection software that was available on the date that the file was posted. The file is stored on security-enhanced servers that help to prevent any unauthorized changes to the file.


Microsoft has confirmed that this is a problem in Microsoft Exchange Server version 5.5. This problem was first corrected in Exchange Server 5.5 Service Pack 4.

  • Microsoft Exchange Server 5.5 Standard Edition
kbnosurvey kbarchive kbhotfixserver kbqfe kbbug kbexchange550presp4fix kbexchange550sp4fix kbfix kbgraphxlinkcritical kbqfe KB243626
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