Article ID: 972701 - View products that this article applies to.
You make a call from a Microsoft Office Communications Server 2007 R2 application that uses the Unified Communications Managed API to another Office Communications Server 2007-based application. However, after some time, the call fails.
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/970679/ )Description of the update package for Office Communications Server 2007 R2, Unified Communications Managed API 2.0 Core Redist 64-bit: July 2009
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
The issue usually occurs when the available IP addresses of the host computer change quickly. In this case, calls fail if the IP addresses for multiple calls must be configured at the same time.