CryptGenKey failed with error

Hello,

I developed some functions based on UCMA 4.0, such as creating conference ,join somebody into conference ,something like that.   the app is working well in my local win7 iis enviroment, however , once it is deployed into win2012 r2 enviroment where UCMA sdk4.40 is already installed, it throw below stack exception, 

do you guys run into the same issue before? thanks for your help in advance. 

 CryptGenKey failed with error 5
Microsoft.Rtc.Signaling.OperationFailureException:CryptGenKey failed with error 5
   at Microsoft.Rtc.Signaling.SipAsyncResult`1.ThrowIfFailed()
   at Microsoft.Rtc.Signaling.Helper.EndAsyncOperation[T](Object owner, IAsyncResult result)
   at Microsoft.Rtc.Collaboration.ConferenceManagement.ConferenceServices.EndScheduleConference(IAsyncResult result)
   at UCMAService.ConferenceSchedule.conferenceEndScheduled(IAsyncResult ar) in D:\Project\UCMAService\UCMA\ConferenceSchedule.cs:line 88
Detected at System.Environment.GetStackTrace(Exception e, Boolean needFileInfo)
   at System.Environment.get_StackTrace()
   at Microsoft.Rtc.Signaling.RealTimeException..ctor(String message, Exception innerException)
   at Microsoft.Rtc.Collaboration.Conferencing.SelfSignedCertificateManager.AquireContext(IntPtr& provHandle)
   at Microsoft.Rtc.Collaboration.Conferencing.SelfSignedCertificateManager.CreateSelfSignedCertificate()
   at Microsoft.Rtc.Collaboration.Conferencing.SelfSignedCertificateManager.Initialize()
   at Microsoft.Rtc.Collaboration.Conferencing.SelfSignedCertificateManager.get_Singleton()
   at Microsoft.Rtc.Collaboration.ConferenceManagement.ConferenceServices.GenerateGetConferenceRequest(Int32 requestId, String conferenceId)
   at Microsoft.Rtc.Collaboration.Conferencing.ConferenceAsyncResult`1.StartServiceRequest()
   at Microsoft.Rtc.Collaboration.Conferencing.ConferenceAsyncResult`1.Start()
   at Microsoft.Rtc.Collaboration.Conferencing.CreateModifyConferenceAsyncResult.SendGetConferenceRequest()
   at Microsoft.Rtc.Collaboration.Conferencing.ConferenceAsyncResult`1.CompletionCallback(IAsyncResult result)
   at Microsoft.Rtc.Signaling.SipAsyncResult2`1.MakeCallback()
   at Microsoft.Rtc.Signaling.SipMessageAsyncResult.MakeCallbackOnThreadPool(Object state)
   at Microsoft.Rtc.Signaling.QueueWorkItemState.ExecuteWrappedMethod(WaitCallback method, Object state)
   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.QueueUserWorkItemCallback.System.Threading.IThreadPoolWorkItem.ExecuteWorkItem()
   at System.Threading.ThreadPoolWorkQueue.Dispatch()
FailureReason = Unknown