A meeting request that is sent from OWA causes a "553 5.0.0 Message-Id header line format error" NDR message in an Exchange Server 2007 environment

When a Microsoft Exchange Server 2007 user sends a meeting request to external recipients by using Microsoft Outlook Web Access (OWA), the Message-ID of the meeting request is a unique GUID. For example, the meeting-ID uses the following format: However, RFC-2822 recommends that the Message-ID should use the following format: Because of this incompatibility, the meeting request from OWA may cause a Non Delivery Report (NDR) message is generated by the external target mail servers sometimes. A specific NDR in this scenario includes the following message:

To resolve this problem, install Update Rollup 8 for Exchange 2007 Service Pack 1. For more information about Update Rollup 8 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.

For more information about RFC-2822, visit the following Web site: