The admob banner is not displayed, only displayed in white

Question

Hello everyone I am working with an admob banner, as I was reading me and I followed those tutorials, try 2 ways 1.- I put the adomob of normal formal following the parameters in the layout in the manifest etc 2.- and the other way is putting the id of the phone since my app is not yet found the playstore, but no way it works for me, it is being displayed in a populateviewholder to be displayed in a recycler view

the xml:

 <LinearLayout android:orientation="vertical"
android:layout_marginTop="55dp"
android:layout_height="match_parent"
android:layout_width="match_parent"
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
xmlns:app="http://schemas.android.com/apk/res-auto">


<android.support.v7.widget.CardView xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    app:cardCornerRadius="0dp"
    android:elevation="20dp"
    android:id="@+id/cardView2">

    <include layout="@layout/layout_post"/>


</android.support.v7.widget.CardView>

<android.support.v7.widget.CardView
    android:id="@+id/cardView"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:elevation="20dp"
    app:cardCornerRadius="0dp">

    <ImageView
            android:id="@+id/iv_post_display"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:adjustViewBounds="true"
            android:src="@drawable/imageholder" />

</android.support.v7.widget.CardView>

<android.support.v7.widget.CardView
    android:layout_marginTop="6dp"
    android:layout_gravity="center"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content">

    <com.google.android.gms.ads.AdView
        xmlns:ads="http://schemas.android.com/apk/res-auto"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        ads:adSize="BANNER"
        ads:adUnitId="@string/id_anuncio"
        android:id="@+id/adViewRanEspanol">

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

</android.support.v7.widget.CardView>

the cardview that contain the AdView, dissapears...

the relevant code

   protected void populateViewHolder(final PostHolder viewHolder, final Post model, int position) {
            Post mPost = new Post();

            viewHolder.mAdView = new AdView(getActivity());
            AdRequest adRequest = new AdRequest.Builder().addTestDevice(AdRequest.DEVICE_ID_EMULATOR).addTestDevice("7775AC7DC1AC628EBAFF1EB0CBF0A4B3").build();
            viewHolder.mAdView.setAdSize(AdSize.BANNER);
            viewHolder.mAdView.setAdUnitId("ca-app-pub-1291200089622969/xxxxx"rest of string" ");
            viewHolder.mAdView.loadAd(adRequest);

the manifest:

 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.android.octa.memetixs">

<uses-permission android:name="android.permission.INTERNET"></uses-permission>
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"></uses-permission>
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

<application
    android:name=".PostApplication"
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher_definitivo"
    android:label="Post it!"
    android:roundIcon="@mipmap/ic_launcher_round"
    android:supportsRtl="true"
    android:theme="@style/AppTheme">
    <activity android:name=".Activities.Log_Reg_Forgot.LogInActivity">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
    <activity android:name=".Activities.Log_Reg_Forgot.RegisterActivity" />
    <activity android:name=".Activities.Log_Reg_Forgot.ForgotActivity" />
    <activity
        android:name=".Activities.main.main_spanish.random.PostActivity"
        android:label="@string/title_activity_post"
        android:theme="@style/AppTheme" />
    <activity android:name=".Activities.misc.OptionActivity" />
    <activity android:name=".Activities.main.main_spanish.random.CommentActivity"></activity>
    <activity android:name=".Activities.main.main_spanish.random.CommentVideoActivity" />


    <activity android:name=".Activities.main.main_english.randomactivitys.PostActivityEng"></activity>
    <activity android:name=".Activities.main.main_english.randomactivitys.CommentActivityEng"></activity>
    <activity android:name=".Activities.main.main_english.randomactivitys.CommentVideoActivityEng"></activity>


    <activity android:name=".Activities.main.main_spanish.memetc.PostActivityMemes"></activity>
    <activity android:name=".Activities.main.main_spanish.memetc.CommentActivityMemes"></activity>
    <activity android:name=".Activities.main.main_spanish.memetc.CommentVideoActivityMemes"></activity>


    <activity android:name=".Activities.main.main_english.memeactivitys.CommentActivityEngMeme"></activity>
    <activity android:name=".Activities.main.main_english.memeactivitys.CommentVideoActivityEngMeme"></activity>
    <activity android:name=".Activities.main.main_english.memeactivitys.PostActivityEngMeme"></activity>


    <activity android:name=".Activities.main.main_spanish.creativo.CommentActivityCreativo"></activity>
    <activity android:name=".Activities.main.main_spanish.creativo.CommentVideoActivityCreativo"></activity>
    <activity android:name=".Activities.main.main_spanish.creativo.PostActivityCreativo"></activity>


    <activity android:name=".Activities.main.main_english.creativeactivities.CommentActivityEngCreative"></activity>
    <activity android:name=".Activities.main.main_english.creativeactivities.CommentVideoActivityEngCreative"></activity>
    <activity android:name=".Activities.main.main_english.creativeactivities.PostActivityEngCreative"></activity>

    <activity android:name=".Activities.main.main_universals.mainWtf.PostActivityWtf"></activity>
    <activity android:name=".Activities.main.main_universals.mainWtf.CommentActivityWtf"></activity>
    <activity android:name=".Activities.main.main_universals.mainWtf.CommentVideoActivityWtf"></activity>

    <activity android:name=".Activities.main.main_universals.mainAdu.CommentVideoActivityAdu"></activity>
    <activity android:name=".Activities.main.main_universals.mainAdu.PostActivityAdu"></activity>
    <activity android:name=".Activities.main.main_universals.mainAdu.CommentActivityAdu"></activity>

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

</application>