Kotlin 无法获取提供程序 com.google.android.gms.ads.MobileAdsInitProvider：java.lang.IllegalStateException

I update my Android Studio (3.2.1) and its sdk to the latest version. After that it required a manual update for Manifest by adding these tags:

<application
    android:allowBackup="true"
    android:icon="@drawable/ic_launcher"
    android:label="@string/app_name"
    android:roundIcon="@drawable/ic_launcher"
    android:supportsRtl="true"
    android:theme="@style/AppTheme"
    tools:ignore="AllowBackup,GoogleAppIndexingWarning">

    <meta-data
        android:name="com.google.android.gms.ads.APP_ID"
        android:value="ca-app-pub-#############"/>

    <activity android:name=".MainActivity">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
    <activity android:name=".NewActivity" />
    <activity android:name=".PreviewActivity" />
    <activity android:name=".EditActivity" />
    <activity
        android:name=".preferencesdata.AboutActivity"
        android:theme="@style/Theme.AppCompat.DayNight.NoActionBar" />
    <activity android:name=".preferencesdata.SettingsActivity"
        android:label="@string/settings">
        <meta-data
            android:name="android.support.PARENT_ACTIVITY"
            android:value=".MainActivity"/>
    </activity>
</application>

whereby instead the app ID I put the real id of my app. The value has also been changed to the right Ad Unit id as shown here https://developers.google.com/admob/android/quick-start. I also called this function in the MainActivity.kt:

MobileAds.initialize(this, resources.getString(R.string.banner_ad_unit_id)) 

然而，这个问题并没有得到解决.它仍然打印如下:

E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.easyapps.cryptnote, PID: 3991
    java.lang.RuntimeException: Unable to get provider com.google.android.gms.ads.MobileAdsInitProvider: java.lang.IllegalStateException: 

    ******************************************************************************
    * The Google Mobile Ads SDK was initialized incorrectly. AdMob publishers    *
    * should follow the instructions LINK to add a valid  *
    * App ID inside the AndroidManifest. Google Ad Manager publishers should     *
    * follow instructions here: LINK.                           *
    ******************************************************************************


        at android.app.ActivityThread.installProvider(ActivityThread.java:5156)
        at android.app.ActivityThread.installContentProviders(ActivityThread.java:4748)
        at android.app.ActivityThread.handleBindApplication(ActivityThread.java:4688)
        at android.app.ActivityThread.-wrap1(ActivityThread.java)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1405)
        at android.os.Handler.dispatchMessage(Handler.java:102)
        at android.os.Looper.loop(Looper.java:148)
        at android.app.ActivityThread.main(ActivityThread.java:5417)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
     Caused by: java.lang.IllegalStateException: 

    ******************************************************************************
    * The Google Mobile Ads SDK was initialized incorrectly. AdMob publishers    *
    * should follow the instructions here: LINK to add a valid  *
    * App ID inside the AndroidManifest. Google Ad Manager publishers should     *
    * follow instructions here: LINK.                           *
    ******************************************************************************


        at com.google.android.gms.internal.ads.zzmn.attachInfo(Unknown Source)
        at com.google.android.gms.ads.MobileAdsInitProvider.attachInfo(Unknown Source)
        at android.app.ActivityThread.installProvider(ActivityThread.java:5153)
            ... 10 more

有人能告诉我为什么会这样，或者帮我解决吗？我试图用谷歌搜索这个问题，但没有解决方案.这似乎是一个尚未解决的新问题.非常感谢.