title: Admob ad not show up when application id is the same in Google Play
body: <p>I uploaded an app to Google play yesterday, but Admob ad not showing up.
  Detail explanation:
  If I change the application id in <code>build.gradle</code> from 
  applicationId <code>com.abcde.alphabetmatchinggame</code>
  to a different name like
  applicationId <code>com.abcde.alphabetmatching</code>,
  then the ad will show up.</p>
  
  <p>Since I have already published my app to Google play using package name (application id) <code>com.abcde.alphabetmatchinggame</code>, so I can not just rename the application id to something else as a work around.</p>
  
  <p>To find out what's happening, I added the adListener and on the call back</p>
  
  <pre><code>public void onAdFailedToLoad(int errorCode)
  </code></pre>
  
  <p>The error is: </p>
  
  <pre><code>public static final int ERROR_CODE_NO_FILL The ad request was successful, but no ad was returned due to lack of ad inventory.
  </code></pre>
  
  <p>This doesn't make sense because changing to another application id that is different from the published one in Google play showing ads right away.</p>
  
  <p>Then I create another ad unit and same thing no ad and same error code.</p>
  
  <p>I am clueless now.  Should I just delete my published app and create a new release under different application id / package name?  But it's such a hassle to delete and wait for Google play to release.</p>