Kentico content staging error on IIS - iis-8

Question

I've inherited a site in two separate staging and production Kentico v6.0.39 sp1 installs that i'm tasked to move from Win2008R2 to a new Win2012 server. I've copied the DBs, and sites completely and adjusted the web.configs. Everything is working except Content Staging.
It's the Content Staging that is throwing the errors in the Event log of the Staging instance:
Description: Message: The underlying connection was closed: An unexpected error occurred on a send.
Stack Trace:
at System.Web.Services.Protocols.WebClientProtocol.GetWebResponse(WebRequest request)
at System.Web.Services.Protocols.HttpWebClientProtocol.GetWebResponse(WebRequest request)
at Microsoft.Web.Services3.WebServicesClientProtocol.GetResponse(WebRequest request, IAsyncResult result)
at System.Web.Services.Protocols.SoapHttpClientProtocol.Invoke(String methodName, Object[] parameters)
at CMS.Synchronization.CMS.SynchronizationEngine.SyncServerWse.ProcessSynchronizationTask(String taskTitle, String taskType, String taskObjectType, String taskData, String taskBinaryData, String taskServerList, String systemVersion)
at CMS.Synchronization.SyncClient.RunTask(TaskInfo taskObj)
at System.Net.Sockets.NetworkStream.Read(Byte[] buffer, Int32 offset, Int32 size)
at System.Net.FixedSizeReader.ReadPacket(Byte[] buffer, Int32 offset, Int32 count)
at System.Net.Security.SslState.StartReceiveBlob(Byte[] buffer, AsyncProtocolRequest asyncRequest)
at System.Net.Security.SslState.StartSendBlob(Byte[] incoming, Int32 count, AsyncProtocolRequest asyncRequest)
at System.Net.Security.SslState.ForceAuthentication(Boolean receiveFirst, Byte[] buffer, AsyncProtocolRequest asyncRequest)
at System.Net.Security.SslState.ProcessAuthentication(LazyAsyncResult lazyResult)
at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Net.TlsStream.ProcessAuthentication(LazyAsyncResult result)
at System.Net.TlsStream.Write(Byte[] buffer, Int32 offset, Int32 size)
at System.Net.ConnectStream.WriteHeaders(Boolean async)
at System.Net.Sockets.NetworkStream.Read(Byte[] buffer, Int32 offset, Int32 size)
It syncs fine over HTTP so im thinking it's it's an IIS8 config issue as the Kentico installs are the same as what is working on the original Win2008 server.
I can browse the site using SSL without error and can browse to the https://www.mykentico.com/CMSPages/syncserver.asmx handler successfully, it's just when i sync that the problem appears.
I know that it's not Kentico anymore once the problem becomes an IIS issue but can you think of anything config setting that would prevent HTTPS content staging?
Any help would be greatly appreciated