Applies to: Exchange Server 2007 SP1, Exchange Server 2007
Topic Last Modified: 2009-04-23

Non-delivery reports (NDRs) are a type of delivery status notification. NDRs are generated whenever a message can't be delivered. If a server detects the reason for the delivery failure, it associates the reason to a status code and a corresponding error message is written.

The following are basic questions that you should consider to troubleshoot NDRs in Microsoft Exchange Server 2007. Gather this information at the beginning of your troubleshooting:

Creating a new test user is always helpful in NDR troubleshooting. Be sure to investigate the time periods when NDRs occur and to obtain any background information that is available about the issue. Be aware of any changing variables that affect the issue. It is important that you narrow the issue as much as possible by asking questions that are similar to those described in the preceding list.

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