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:

What types of clients are used (for example, Microsoft Office Outlook 2007, Outlook 2003, or Outlook 2002)?
Do one or more users receive NDRs when they send mail to a specific recipient or to every recipient?
Can other users send mail successfully to the same recipient from the same server?
Do users on a specific server experience this issue, or do users on multiple servers experience the same issue?
Is the issue site-specific, or does the issue occur in multiple sites?
Can you reproduce the issue on demand, or does it occur randomly?
If the NDRs are random, what is the frequency of the NDRs?
What type of recipient is experiencing the problem? Where does the recipient physically reside?
How was the recipient entered in the To field of the message (for example, selected from the global address book, selected from a personal address book, or manually typed)?

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.

For More Information

For more information about NDRs, see the following topics:

Exchange 2007

Non-Delivery Report Issues