Solved: No resource identifier found for attribute ‘configchanges’ in package ‘android’

I was following the Xamarin forms tutorial to integrate AdMob and following error came up

No resource identifier found for attribute 'configchanges' in package 'android'

No matter what I did and tried to find on the internet but could not find the fix. Finally I tried to look very closely and found a small mistake. Here is what I copied from the tutorial

<activity android:name="com.google.android.gms.ads.AdActivity" android:configchanges="keyboard|keyboardHidden|orientation|screenLayout|uiMode|screenSize|smallestScreenSize" android:theme="@android:style/Theme.Translucent"></activity>

Instead, it should be

<activity android:name="com.google.android.gms.ads.AdActivity" android:configChanges="keyboard|keyboardHidden|orientation|screenLayout|uiMode|screenSize|smallestScreenSize" android:theme="@android:style/Theme.Translucent"></activity>

Notice that “C” in android:configChanges is capital.

That solved the issue.