Consider the following scenario:
You have a Microsoft Lync Server 2010 environment that has applied the updates that are mentioned in Microsoft Knowledge Base (KB) article 2670534.
You join a meeting by using Lync Web App.
You try to share an application in the meeting.
In this scenario, you cannot share the application. Additionally, you do not receive an error message.
Note If this is the first time that you have shared an application in the meeting, you are prompted to install or update the Lync Web App plug-in.
This issue occurs because the Lync Web App plug-in handles the media relay host name incorrectly. When you try to share the application, the media relay host name in the Media Relay Authentication Service (MRAS) response is returned to the Lync Web App plug-in instead of the media relay address. However, the Lync Web App plug-in ignores the host name because it can only recognize an IP address. Therefore, the following message is missing from the INVITE request:
a=candidate:<candidate> 1 <TCP Passive/Active> <packet size><IP address and port> type relay raddr <relay IP address and port>
Note When you try to share an application, the MRAS response is returned to the Lync Web App Plug-in.
To resolve the issue, install the following cumulative update:
2737902 Description of the cumulative update for Lync Server 2010, Web Components Server: October 2012
For more information, click the following article number to view the article in the Microsoft Knowledge Base:
2670534 Description of the cumulative update for Lync Server 2010, Web Components Server: February 2012 For more information about remote conferencing with Lync Web App with Forefront Threat Management Gateway 2010 reverse proxy: part 2, go to the following Microsoft website: