title: Error loading rewarded video ad with different errors for each device
body: <p>I am trying to show rewarded video ads in my app and every time i try and load the ad, it goes straight to the "failed to load ad" method.</p>
  
  <p>For my phone i get the error:</p>
  
  <pre><code>W/Ads: Fail to instantiate adapter com.google.ads.mediation.chartboost.ChartboostAdapter
         android.os.RemoteException
             at com.google.android.gms.internal.zzgy.zzbx(Unknown Source)
             at com.google.android.gms.internal.zzgy.zzbw(Unknown Source)
             at com.google.android.gms.internal.zzgy.zzbu(Unknown Source)
             at com.google.android.gms.internal.zzgz$zza.onTransact(Unknown Source)
             at android.os.Binder.transact(Binder.java:387)
             at com.google.android.gms.ads.internal.mediation.client.d.a(:com.google.android.gms.DynamiteModulesA:94)
             at com.google.android.gms.ads.internal.reward.c.b(:com.google.android.gms.DynamiteModulesA:220)
             at com.google.android.gms.ads.internal.reward.mediation.j.a(:com.google.android.gms.DynamiteModulesA:1140)
             at com.google.android.gms.ads.internal.util.b.run(:com.google.android.gms.DynamiteModulesA:19)
             at com.google.android.gms.ads.internal.util.y.call(:com.google.android.gms.DynamiteModulesA:1055)
             at com.google.android.gms.ads.internal.util.z.run(:com.google.android.gms.DynamiteModulesA:75)
             at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:423)
             at java.util.concurrent.FutureTask.run(FutureTask.java:237)
             at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1113)
             at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:588)
             at java.lang.Thread.run(Thread.java:818)
  </code></pre>
  
  <p>For the emulator I am using, I get the error: </p>
  
  <pre><code>There was a problem getting an ad response. ErrorCode: 0
  </code></pre>
  
  <p>Also, I am assuming that the problem is not with admob as I have implemented banner ads with no problem. I am using chartboost as a meditaion.</p>
  
  <pre><code>import com.google.ads.mediation.admob.AdMobAdapter;
  import com.google.android.gms.ads.AdRequest;
  import com.google.android.gms.ads.AdView;
  import com.google.android.gms.ads.MobileAds;
  import com.google.android.gms.ads.reward.RewardItem;
  import com.google.android.gms.ads.reward.RewardedVideoAd;
  import com.google.android.gms.ads.reward.RewardedVideoAdListener;
  import com.chartboost.sdk.Chartboost;
  import com.chartboost.sdk.CBLocation;
  import com.chartboost.sdk.ChartboostDelegate;
  
  public class Settings extends AppCompatActivity
          implements NavigationView.OnNavigationItemSelectedListener, RewardedVideoAdListener {
  
      SharedPreferences data;
      final String filename = "Data";
  
      Button btnAds;
      Button btnResetData;
      Button btnHelp;
      long adtime;
  
      private RewardedVideoAd mAd;
  
      @Override
      protected void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);
          Chartboost.startWithAppId(this, "I have insterted my app id here", "and my app signature here");
          Chartboost.onCreate(this);
  
          setContentView(R.layout.activity_settings);
          Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
          setSupportActionBar(toolbar);
  
          btnAds = (Button) findViewById(R.id.btnAds);
          btnResetData = (Button) findViewById(R.id.btnResetData);
          btnHelp = (Button) findViewById(R.id.btnHelp);
  
          DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
          ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
                  this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
          drawer.setDrawerListener(toggle);
          toggle.syncState();
  
          NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
          navigationView.setNavigationItemSelectedListener(this);
  
          btnAds.setText("Loading ad...");
  
          // Load an ad into the AdMob banner view.
          AdView adView = (AdView) findViewById(R.id.adView);
          AdRequest adRequest = new AdRequest.Builder()
                   .setRequestAgent("android_studio:ad_template").build();
          adView.loadAd(adRequest);
  
          mAd = MobileAds.getRewardedVideoAdInstance(this);
          mAd.setRewardedVideoAdListener(this);
          loadRewardedVideoAd();
      }
      private void loadRewardedVideoAd() {
              mAd.loadAd("I have inserted my app unit id here", new AdRequest.Builder().build());
      }
  }
  </code></pre>
  
  <p>I've also got the other "after reward" methods and "on back" methods after</p>