title: Banner Google Ad not display - Ad failed to load: LoadAdError(code: 3, domain: com.google.android.gms.ads, message: No ad config.)
body: <p>I get this error when use the banner test ad unit id : ca-app-pub-3940256099942544/6300978111
  in AndroidManifest.xml I use ca-app-pub-3940256099942544~4354546703 - the id of example project.</p>
  <blockquote>
  <p>Ad failed to load with error: LoadAdError(code: 3, domain:
  com.google.android.gms.ads, message: No ad config., responseInfo:
  ResponseInfo(responseId: null, mediationAdapterClassName: ,
  adapterResponses: []))</p>
  </blockquote>
  <p>But when I run the sample project which uses this id, it still works fine.</p>