error

2021-05-25 23:24:55.448 7449-7449/red.simpleapp.youtubekids E/AndroidRuntime: FATAL EXCEPTION: main
    Process: red.simpleapp.youtubekids, PID: 7449
    java.lang.RuntimeException: Unable to get provider com.google.android.gms.ads.MobileAdsInitProvider: java.lang.IllegalStateException:

    ******************************************************************************
    * Invalid application ID. Follow instructions here:                          *
    * https://googlemobileadssdk.page.link/admob-android-update-manifest         *
    * to find your app ID.                                                       *
    ******************************************************************************


        at android.app.ActivityThread.installProvider(ActivityThread.java:7244)
        at android.app.ActivityThread.installContentProviders(ActivityThread.java:6780)
        at android.app.ActivityThread.handleBindApplication(ActivityThread.java:6697)
        at android.app.ActivityThread.access$1300(ActivityThread.java:237)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1913)
        at android.os.Handler.dispatchMessage(Handler.java:106)
        at android.os.Looper.loop(Looper.java:223)
        at android.app.ActivityThread.main(ActivityThread.java:7656)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947)
     Caused by: java.lang.IllegalStateException:

    ******************************************************************************
    * Invalid application ID. Follow instructions here:                          *
    * https://googlemobileadssdk.page.link/admob-android-update-manifest         *
    * to find your app ID.                                                       *
    ******************************************************************************


        at com.google.android.gms.internal.ads.zzxw.attachInfo(com.google.android.gms:play-services-ads-lite@@18.3.0:20)
        at com.google.android.gms.ads.MobileAdsInitProvider.attachInfo(com.google.android.gms:play-services-ads-lite@@18.3.0:3)
        at android.app.ActivityThread.installProvider(ActivityThread.java:7239)
        	... 10 more