ASP.NET Identity OWIN Middleware Google OAuth2 AuthenticationManager SignIn not working

Question

I have created a simple ASP.NET MVC4 web site to test the new OWIN Authentication middleware, I decided to start with Google OAuth2, I have had struggle quite a bit with the

Answer 1

I had the same problem but all I needed to do was add "Google + API" to my list of APIS in the google developer console. After that, everything worked.