Proguard

If you are using proguard in your app, you must add the following lines to your setup file:

-keepattributes *Annotation*
-keepclassmembers class com.google.**.R$* {
    public static *;
}
-keep public class com.google.ads.** {*;}
-keep public class com.google.android.gms.** {*;}
-keep public class com.tappx.** { *; }