When you send e-mail from Outlook to a non-SMTP address, you receive a non-delivery report message if your organization includes Exchange Server 2007

You are running a Microsoft Exchange Server environment that includes Exchange Server 2007. You are using Microsoft Office Outlook 2007 or Microsoft Office Outlook 2003 in cached mode on a client computer. You send an e-mail message from Outlook on the client computer to a non-Simple Mail Transfer Protocol (SMTP) address. For example, you address the e-mail message to an address, such as FAX. In this scenario, you receive a non-deliverable report (NDR) message that resembles the following message:

This problem can occur in several circumstances. Outlook generates an NDR message when one of the following conditions is true:

• If you do not have an SMTP connector that includes the required address space type.
• If you have an address space that is scoped to the whole Exchange organization in a custom connector, and the custom connector is configured on a computer that is running Exchange 2000 Server or an Exchange Server 2003.

To resolve this problem, follow these steps:

1. Create a new Send connector on the Exchange Server 2007 computer. Make sure that this connector includes the required custom address space type and that the connector points to a smart host. For more information about how to create a Send connector in Exchange Server 2007, visit the following Microsoft Web site:
   http://technet.microsoft.com/en-us/library/aa998814.aspx
2. Restart the Microsoft Exchange Information Store service in the Services snap-in. This updates the registry entry on the client.
3. Restart Outlook.
4. Send e-mail to the custom address.

Outlook 2007 and Outlook 2003 maintain a list of "allowed" address types in the registry. Outlook hands over messages that are addressed to an "allowed" address type to Exchange Server for further processing. When messages are addressed to an address type that is not included in the "allowed" list, Outlook does not reference Exchange Server but immediately returns an NDR message.

This list in the registry is refreshed every time that Outlook starts a MAPI session in cached mode. This list is stored in the 01026687 registry entry under the following registry subkey:

For more information about address spaces and connector scope, visit the following Microsoft Web site, and see the "Address Spaces and Connector Scope" section: