Debugging WCF: Unable to automatically step into the server. The remote procedure could not be debugged.

I kept getting the following error all of a sudden when I was debugging a WCF client: "Unable to automatically step into the server. The remote procedure could not be debugged."

The WCF service is hosted by IIS. The client is a WinForm application. Both projects reside within the same solution. When I received the error message, I checked to make sure that the WCF service host's web.config has the debug flag set to true as follows: <compilation debug="true">. But I was still getting the same error. Then it dawned on me that I had changed the binding from wsHttp to wsDualHttp and wonder it that was the cause. So I reverted it back to wsHttp binding and I was able to step through the serive code when debugging the client.

I'll have to look up why that is when I get a chance from my project.