title: Admob error code 2 - Ad failed to load : 2
body: <p>I am trying to show a smart size banner in android, but the ad isn't showing and when I see the logs it says: <code>I/Ads: Ad failed to load : 2</code>.
  I searched on the internet and found that issue is due to internet connection, but I have active and reliable net connection on my phone.
  Below is my <code>app</code> gradle:</p>
  
  <pre><code>dependencies {
      implementation fileTree(dir: 'libs', include: ['*.jar'])
      androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
          exclude group: 'com.android.support', module: 'support-annotations'
      })
      implementation 'com.android.support:appcompat-v7:28.0.0'
      implementation 'com.android.support:design:28.0.0'
      implementation 'com.android.support.constraint:constraint-layout:2.0.0-alpha3'
      implementation 'com.android.support:support-v4:28.0.0'
      testCompile 'junit:junit:4.12'
      implementation 'com.airbnb.android:lottie:2.1.0'
      implementation 'com.mikhaellopez:circularimageview:3.2.0'
      implementation 'com.google.android.gms:play-services-ads:17.1.2'
  }
  </code></pre>
  
  <p>and below is my activity class:</p>
  
  <pre><code>MobileAds.initialize(this, Utils.ADMOB_APP_ID);
          mAdView = findViewById(R.id.adView);
          AdRequest adRequest = new AdRequest.Builder().addTestDevice("B2DD8C77E01892E0FF2A672FC77E2FF9").build();
          mAdView.loadAd(adRequest);
  </code></pre>
  
  <p>and this is the layout:</p>
  
  <pre><code>&lt;com.google.android.gms.ads.AdView
              xmlns:ads="http://schemas.android.com/apk/res-auto"
              android:id="@+id/adView"
              android:layout_width="match_parent"
              android:layout_height="wrap_content"
              android:layout_centerHorizontal="true"
              android:layout_alignParentBottom="true"
              ads:adSize="SMART_BANNER"
              ads:adUnitId="@string/app_admob_id"&gt;
          &lt;/com.google.android.gms.ads.AdView&gt;
  </code></pre>
  
  <p>and this is the some of error log related to the ads:</p>
  
  <pre><code>W/Ads: Invoke Firebase method getInstance error.
      The Google Mobile Ads SDK will not integrate with Firebase. Admob/Firebase integration requires the latest Firebase SDK jar, but Firebase SDK is either missing or out of date
  W/Ads: Not retrying to fetch app settings
  I/Ads: Ad failed to load : 2
  </code></pre>