A bit background:
We have a soultion built on UCMA conference. All parties join the conference using BackToBackCall via trusted application endpoint. The issue is:
Supervisor monitoring: The client application built on Lync SDK is running on supervisor's desktop. When he/she starts monitoring a session, the application will initialize an outbound conversation to a trusted application endpoint which will in turn backtoback the call to conference once it detects the incoming calll from the supervior. Sometime the client application on supervior's desktop fails to create the outgoing conversation with the following exception:
System.InvalidCastException: Unable to cast COM object of type 'Microsoft.Office.Uc.ConversationManagerClass' to interface type 'Microsoft.Office.Uc.IConversationManager'. This operation failed because the QueryInterface call on the COM component for the
interface with IID '{C31FB52D-9E9E-45AD-A102-5218E1685B78}' failed due to the following error: The RPC server is unavailable. (Exception from HRESULT: 0x800706BA).
at System.StubHelpers.StubHelpers.GetCOMIPFromRCW(Object objSrc, IntPtr pCPCMD, IntPtr& ppTarget, Boolean& pfNeedsRelease)
at Microsoft.Office.Uc.ConversationManagerClass.AddConversation()
at Microsoft.Lync.Model.Conversation.ConversationManager.AddConversation()
I assume there is something wrong with the COM service running inside Lync client.
Any help is much appreciated.