Whiteboard not Working on Fresh Lync 2013 Standard Edition Server

I came across this when deploying Lync to a Server 2012 R2 for the first time. Voice, video calls and desktop sharing was working as expected. However when trying to open a whiteboard the client was showing a generic 'Network issues' error message. 

When trying to open the whiteboard, the following errors were logged on the front end server:

 Event ID 51021 , Source LS MCU Factory

The MCUFactory failed to find an Web Conferencing Server to service an web conferencing modality request.

Cause: All Web Conferencing Servers are unavailable or overloaded.

Resolution:

Verify that all Web Conferencing Servers are available and not overloaded. If overloaded deploy and extra server to distribute load.

Event ID 32069 , Source LS User Services

The Mcu Factory returned failure for a request sent to it. Conferencing requests for this Mcu type will be retried but if this error continues to occur conferencing functionality will be affected.

Mcu Type: data-conf

Cause:Mcu factory not being provisioned or functioning incorrectly.

Resolution:

Ensure that the Mcu Factory is provisioned and functioning correctly. If any network related errors are reported by the Mcu Factory ensure that they are resolved.

  

Now these errors weren't exactly helpful, as this was a new install of Lync 2013 so we had a 10 pilot users on there. So there is no way it could be an overloaded conferencing server.

I started looking at Lync 2013 with 2012 R2 issues and came across
this Microsoft KB article: http://support.microsoft.com/kb/2901554/en-us 

This doesn't mention the errors I was getting above, but I thought I'd give it a go anyway. 

Resolution:

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:
   HKLM\System\CurrentControlSet\Control\SecurityProviders\Schannel
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:
   Stop-CsWindowService
   
   Start-CsWindowsService

After doing these steps, whiteboards started working immediately! As stated in the KB article, it's a fully supported workaround for Lync 2013. So I'll be doing this on all deployments going forward on Server 2012 R2 until Microsoft fixes it.