Article ID: 972709 - View products that this article applies to.
When a federated partner sends a Session Initiation Protocol (SIP) message request, Microsoft Office Communications Server 2007 R2 returns the following generic SIP error message:
500: Server Internal Error
The SIP stack implementation of the federated partner does not copy the EPID parameter from the "To" header of the 200 OK message to the "To" header of the ACK message.
To resolve this issue, apply the following update:
For more information, click the following article number to view the article in the Microsoft Knowledge Base:
(http://support.microsoft.com/kb/969821/ )Description of the update package for Office Communications Server 2007 R2: July, 2009