SCCM stopped WSUS Sync

All of a sudden our SCCM server on a disconnected network has decided to just not sync anymore, no idea why it has happened no changes have been made but from a bit of googling I found this in the wsyncmgr.log
Sync failed: The operation has timed out. Source: Microsoft.UpdateServices.Internal.DatabaseAccess.ApiRemotingCompressionProxy.GetWebResponse

In the Component Status for SMS_WSUS_SYNC_MANAGER:
WSUS Synchronization failed.
Message: UssInternalError: InvalidOperationException: .
Source: Microsoft.SystemsManagementServer.SoftwareUpdatesManagement.WsusSyncAction.WSyncAction.SyncWSUS.
The operating system reported error 2147500037: Unspecified error

It's quite annoying as this was working just fine in the middle of July but now nope July & August updates are either not downloading for July when I create my Software Update Group or as in August updates I run my monthly robocopy to put them on the SCCM Server, run the wsusimport and the next day sync the updates and that is where it is now all going wrong.

I have the feeling that I am going to have to remove the Software Update Point and the SCCM Instance on my db server, but do not want to do that today or Friday, unless anyone has any other ideas, I have done extensive research and it all leads to the removal and re-installation of the SUP. 
Any help would be gratefully received.