Unknown Error : Banner Ad

[KChavda18]

Code Implementation :
AdView adView = new AdView(this, "271995593270465_271996219937069", AdSize.BANNER_HEIGHT_50);//438544203147216_438545493147087
AdSettings.addTestDevice(hashKey());
adViewContainer.addView(adView);
adView.setAdListener(new AdListener() {
@OverRide
public void onError(Ad ad, AdError adError) {
Toast.makeText(MainActivity.this, "Error: " + adError.getErrorMessage(), Toast
.LENGTH_LONG).show();
}

        @Override
        public void onAdLoaded(Ad ad) {
            Toast.makeText(MainActivity.this, "Ad loaded!", Toast.LENGTH_LONG).show();
        }

        @Override
        public void onAdClicked(Ad ad) {
            Toast.makeText(MainActivity.this, "Ad clicked!", Toast.LENGTH_LONG).show();
        }

        @Override
        public void onLoggingImpression(Ad ad) {
            Toast.makeText(MainActivity.this, "onLogging", Toast.LENGTH_LONG).show();
        }
    });
    adView.loadAd();

But, it's toast Unknown error

Help me to short out this issue....

[L33tcodex0r]

271995593270465_271996219937069 is not valid, it doesn't belong to a valid app.