Visual Studio shows these errors:
error: cannot access AutoSizeableTextView
public class ButtonRenderer
class file for android.support.v4.widget.AutoSizeableTextView not found - file: \obj\Debug\81\android\src\md5f92e0daf340890c9667469657ee2ece8\ButtonRenderer.java
error: cannot access NestedScrollingChild2
public class ItemsViewRenderer
class file for android.support.v4.view.NestedScrollingChild2 not found - file: \obj\Debug\81\android\src\md51558244f76c53b6aeda52c8a337f2c37\ItemsViewRenderer.java
error: cannot access NestedScrollingParent2
public class SwipeDismissBehavior_OnDismissListenerImplementor
class file for android.support.v4.view.NestedScrollingParent2 not found - file: \obj\Debug\81\android\src\mono\android\support\design\widget\SwipeDismissBehavior_OnDismissListenerImplementor.java
error: cannot access TintableImageSourceView
public class ImageButtonRenderer
class file for android.support.v4.widget.TintableImageSourceView not found - file: \obj\Debug\81\android\src\md51558244f76c53b6aeda52c8a337f2c37\ImageButtonRenderer.java
I installed some packages that I think caused the problem: I installed OneSignal, and the AppLinks, that required installing Xamarin.GooglePlayServices.Base and Xamarin.GooglePlayServices.Basement. then had some conflicts between Android specific packages, I removed all packages I installed down to OneSignal. I deleted the bin and obj folder, did clean and build the project, and restarted Visual Studio, but the problem doesn't go away!