Lync Server Front End: Lost connection to the Web Conferencing Edge Server

I have seen this problem in a couple of deployments now and have decided to share this information since there is not much about it on the web.

The problem

Event ID 41024 – Lost connection to all Web Conferencing Edge Services
Event ID 41024 – Lost connection to the Web Conferencing Edge Server
Event ID 41025 – Connection to the Web Conferencing Edge Server has been restored

These Event ID’s appears every five minutes on the Lync Front End Server, but not in all implementations. I don’t know why it is in only some implementations.

The Resolution

Disable IPv6 on the Front End server. When implementing Exchange 2007 and 2010 we often came across a similar problem where the resolution was to disable IPv6. Disabling IPv6 has cleared the Event ID errors in the cases I have seen. To disable IPv6 properly don’t just uncheck IPv6 on the network adapter, but do it in registry and reboot. See this KB article for how to disable IPv6 properly: http://support.microsoft.com/kb/929852

Screens of the exact Event ID’s