Project reference DLL not found. file not found exception

I have three class library. Provider library is created using SDL Project Template. Other two are simple class library

In my solution, TerminologyProvider.Service project and TerminologyProvider.UI project referenced into TerminologyProvider class library project.

Once build the solution, its successful. I can see TerminologyProvider into SDL studio as well. But once i click on that it throws error like "TerminologyProvider.Service.dll file not found exception".

Please assist to resolve file not found exception. I can see TerminologyProvider.Service.dll AND TerminologyProvider.UI.dll in to bin folder of TerminologyProvider project.