loadAd always fail to load, errorcode 3

Here is my code, i put the NativeExpressAdView in a dialog, but it always return error code 3

NativeExpressAdView adView = new NativeExpressAdView(activity);
adView.setAdSize(new AdSize(280, 250));
adView.setAdUnitId("my-ad-unit");
adView.setVideoOptions(new VideoOptions.Builder()
        .setStartMuted(true)
        .build());
 adView.setAdListener(new AdListener() {
          @Override
          public void onAdFailedToLoad(int i) {
                 super.onAdFailedToLoad(i);
          }
});
adLinearLayout.addView(adView);
adView.loadAd(new AdRequest.Builder().addTestDevice("my-device-id").build());

logcat:

03-27 16:30:21.241 21093-21093/com.xxx.xxx I/Ads: Starting ad request.
03-27 16:30:21.618 21093-22617/com.xxx.xxx I/Ads: No fill from ad server.
03-27 16:30:21.619 21093-21093/com.xxx.xxx I/Ads: Scheduling ad refresh 30000 milliseconds from now.
03-27 16:30:21.619 21093-21093/com.xxx.android W/Ads: Failed to load ad: 3

But it’s working good if i change adUnitId to the one in sample project you provided. What may cause this problem???

[ericleich]

A newly created ad unit will take an hour, but changes to settings should be faster (guessing 10-15 minutes if not sooner).

I have an open feature request against the front-end team to expose this in the front-end, since this is really where this information should be!

[lumenghz]

I’ve tested, my unit id worked as expected. I think maybe you guys can provide a document that can explain this to developers. Thank you @ericleich 😺