Getting error message when building xamarin forms sample application

Facing the below error message when building xamarin forms sample application

"Could not load file or assembly 'netstandard, Version=2.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51' or one of its dependencies. The system cannot find the file specified. sample_app\App.xaml"

Tools used
Visual Studio 2017 Community
Xamarin forms for Android

Please let me know if anyone know the solution

Thanks