Installed Forms.GoogleMaps and got a System.TypeLoadException

I hava a xamarin forms solution where I try to insert GoogleMaps (using nuget)
https://github.com/amay077/Xamarin.Forms.GoogleMaps

But after I added it I get an exception after the splashscreen has been showed and I Init the Forms.

Exception is
System.TypeLoadException: Could not resolve type with token 0100000e

Got it at this line of droid app
global::Xamarin.Forms.Forms.Init(this, bundle);

Kind of new to xamarin development so I need help finding what causes this exception. I'm guessing there is an error adding some dll or something?