Object reference not set to an instance of an object When I create new Android App (Visual Studio)

Question

In a Visual Studio 2015, Xamarin, Android SDK, jdk 1.7, and emulator are installed and Xamarin has all green checked items in tools>options>Xamarin. But When I try to create

Answer 1

I also encounter this problem on Visual Studio 2015 Update 2 with Xamarin.VisualStudio_4.0.3.214, but I solved it by installing level 19, 21, 22, 23 through Android SDK Manager.