Article ID: 2251690 - View products that this article applies to.
When you make a Public Switched Telephone Network (PSTN) call to a Response Group number that is hosted in a Microsoft Office Communications Server 2007 R2 environment, the call disconnects. In addition, a message that resembles the following is logged on the Office Communications Server 2007 R2, Front-end server:
This issue occurs because of an SignalingSession.BeginParticipate exception. This exception causes Mediation Server to send a BYE request to the gateway, which disconnects the call.
To fix this problem, install the following cumulative update:
(http://support.microsoft.com/kb/982170/ )Description of the cumulative update for Office Communications Server 2007 R2, Unified Communications Managed API 2.0 Core Redist 64-bit: July 2010
Microsoft has confirmed that this is a bug in the Microsoft products that are listed in the "Applies to" section.
For more information about the latest updates for Communications Server 2007 R2, click the following article number to view the article in the Microsoft Knowledge Base:
(http://support.microsoft.com/kb/968802/ )Updates for Communications Server 2007 R2