E/Ads:无法获取 isAdIdFakeForDebugLogging,错误代码为 3

E/Ads: Fail to get isAdIdFakeForDebugLogging with error code 3

我的应用程序中的广告昨天在调试模式下正常工作,但今天我收到此错误

2019-04-06 05:08:47.412 12191-12286/www.pro_cs_is.com E/Ads: Fail to get isAdIdFakeForDebugLogging
    java.io.IOException: Connection failure
        at com.google.android.gms.ads.identifier.a.a(:com.google.android.gms.policy_ads_fdr_dynamite@30000@30000.238272502.238272502:68)
        at com.google.android.gms.ads.internal.util.d.d_(:com.google.android.gms.policy_ads_fdr_dynamite@30000@30000.238272502.238272502:4)
        at com.google.android.gms.ads.internal.util.b.run(:com.google.android.gms.policy_ads_fdr_dynamite@30000@30000.238272502.238272502:3)
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:458)
        at java.util.concurrent.FutureTask.run(FutureTask.java:266)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641)
        at java.lang.Thread.run(Thread.java:764)
2019-04-06 05:08:48.772 12191-12191/www.pro_cs_is.com E/AD ERROR: error code3
2019-04-06 05:09:04.314 12191-12191/www.pro_cs_is.com E/AD ERROR: error code3
2019-04-06 05:09:08.344 12191-12191/www.pro_cs_is.com E/AD ERROR: error code3

清单元数据

 <meta-data
            android:name="com.google.android.gms.ads.APPLICATION_ID"
            android:value="@string/ADMOB_APP_ID"/>

MainActivity 广告 xml

 <com.google.android.gms.ads.AdView xmlns:ads="http://schemas.android.com/apk/res-auto"
        android:id="@+id/mainActivityBanner"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        ads:adSize="BANNER"
        ads:adUnitId="@string/MainActivityBanner"
        android:visibility="visible"
        >

    </com.google.android.gms.ads.AdView>

我尝试了广告单元测试及其工作,但我的单元没有

在我 postedGoogle 移动广告 SDK 技术论坛 之后,他们回复了

"I suggest to load test ads instead of live ads to avoid invalid activities. You may do this with your live Ad Unit ID and enabling test device. The error code 3 that you encountered means that an ad request is successful but it can't return ads due to lack of ad inventory. Also, please note that that loading your Ad Unit IDs on an unpublished app may have an impact fill rate."

在我发布应用后,广告成功展示