Lync 2013 – This can happen if the HTTPS certificate has expired, or is untrusted. The certificate serial number is attached for reference. Event ID 32042

By |2017-12-07T14:23:56+00:00February 27th, 2014|Skype|0 Comments

Morning All,

So today I was having some strange issues with conferencing with Lync 2013.

I noticed that I couldn’t share PowerPoint, whiteboard, polls or Q & A, the icons were missing all web conferencing functionality was gone!

So I checked the conferencing policy and they were all enabled so I decided to check the Lync Front End Server Event Log and there were some errors relating to the MCU and certificate errors. I checked certificates and all was ok and then I noticed the event id 32042 below

Description: The DATAMCU was not able to stay connected to the Front End over the C3P channel (HTTPS Connection).
The Web Conferencing Server failed to send C3P notifications to the focus at https:// <>:444/LiveServer/Focus.

This was clearly a reason for the strange conferencing behavior I was having so I researched this a little more and found a fix from Microsoft. This was related to Windows Server 2012 R2 and the change to TLS session caching behavior that was affecting Lync 2013 and there is a workaround by applying a reg key.



Martin B


  • You can disable this value without compromising the security of the system. The system will revert to handling TLS sessions exactly like the sessions were negotiated in earlier Windows Server operating systems.
  • Lync Server 2013 is supported by Windows Server 2012 R2 when this registry workaround is performed.
  1. Click Start, type regedit in the Start search box, and then click regedit.exe in the results list.
  2. Locate the following registry subkey:


  3. Right-click Schannel, and then click New DWORD (32-bit) value.
  4. Type EnableSessionTicket, then press Enter.
  5. Right-click EnableSessionTicket, and then click Modify.
  6. Change the existing value to 2, and then press Enter.
  7. Exit Registry editor.
  8. Open the Lync Server Management Shell.
  9. Run the following Lync Server PowerShell commands in the given order:


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