title: FirebaseInitProvider: FirebaseApp initialization unsuccessful
body: <p>We have followed the <a href="https://firebase.google.com/docs/android/setup">Add Firebase to your Android Project</a> but we can't see the app receiving data in the Firebase Console.<br>
  And when we launch the app, the log says:</p>
  
  <pre><code>FirebaseInitProvider: FirebaseApp initialization unsuccessful
  </code></pre>
  
  <p>What does this mean? What are we doing wrong?<br>
  I can't find this error in the docs, nor here in StackOverflow.</p>