Exchange Server 2007 cannot route e-mail messages to mail enabled Non-MAPI public folders that are hosted on an Exchange Server 2003 server

In an Exchange Server 2003 and Exchange Server 2007 coexist environment, you create a Non-MAPI public folder on Exchange Server 2003 and enable the mail feature for the public folder. However, when an Exchange 2007 user sends a message to the mail enabled Non-MAPI public folder, the message stays in the "Unreachable Domain" queue on the Exchange 2007 Hub Transport server. If you check the message in Exchange Management Console by using the Queue Viewer tool, the Last Error column shows the following error: Eventually, the user receives the following non-deliver report (NDR) message:

This issue occurs because Exchange Server 2007 does not support to route a message to the mail enabled non-MAPI public folders.

To resolve this problem, install Update Rollup 7 for Exchange 2007 Service Pack 1. For more information about Update Rollup 7 for Exchange Server 2007 Service Pack 1, see the following Exchange Help topic: For more information about how to obtain the latest Exchange service pack or update rollup, see the following Exchange Help topic:

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.