title: I can't receive notifications when screen is lock
body: <p>I'm working with Firebase to send Push notification. When I have the app minimized and the screen lock and Data network on 3G, and batery at 90%, I can't receive notifications. I need to receive notifications while the screen is locked.</p>
  
  <p>I noted this in the log at the moment to screen lock.</p>
  
  <pre><code>2019-06-13 16:40:35.901 2372-9542/? D/MC_BatteryStatsData: operate removing wakelock wake:com.exampleapp/.FCMListenerService
  </code></pre>
  
  <p>This is for a Moto C Android version 7.</p>
  
  <p>I tried to add this permission to the manifest file.</p>
  
  <pre><code>&lt;uses-permission android:name="android.permission.WAKE_LOCK"/&gt;
  </code></pre>
  
  <p>Disabled battery saver. It is in the menu <code>Settings -&gt; Battery</code>. </p>
  
  <p>And here is my <code>FCMInstanceIDListenerService.java</code></p>
  
  <pre><code>public class FCMInstanceIDListenerService extends FirebaseInstanceIdService {
  
      private static final String TAG = "MyInstanceIDLS";
  
      @Override
      public void onTokenRefresh() {
          String refreshedToken = FirebaseInstanceId.getInstance().getToken();
          MetodosRepo.setPreference(getBaseContext(), Globals.DEVICE_TOKEN, refreshedToken);
      }
  
  }
  </code></pre>
  
  <p>And the <code>FMCListenerService.java</code></p>
  
  <pre><code>public class FCMListenerService extends FirebaseMessagingService {
  
      @Override
      public void onMessageReceived(RemoteMessage message) {
          Log.e(_TAG, "onMessageReceived");
      }
  }
  </code></pre>
  
  <p>I expect to receive a notification while the screen is locked.º</p>