Push plugin don't receives automatically the notifications sent when the app was close or device shutdown

I sent several notifications to my app when it’s closed and/or the device is shutdown. When I open my app and setup the receive notifications listener I don’t receive any notification.

But, after that, if I send a new notification I receive all the notifications not received before.

Why is it happening and how could I foorce push plugin to receive all sent notifications automatically?

Here is my push provider:

@Injectable()
export class PushProvider {
  
  messages: any;
	
  init(){
  	var push = Push.init({
        android: {
          senderID: "452854818286"
        },
        ios: {
          alert: "true",
          badge: true,
          sound: 'false'
        },
        windows: {}
      });
      push.on('registration', (data) => {
        console.log('REGISTRATION ID', data.registrationId);
      });
      this.messages = new Observable(observer=>{        
        push.on('notification', (data) => {              
          observer.next(data);
        });
      });

      push.on('error', (e) => {
        console.log(e.message);
      });
  } 
}

Solved!

The problem was a GCM configuration backend in the backend not in my app front end.

According to this documentation “delay_while_idle” must be set as true.

Changing this property makes the messages to be delivered even if the device is turned off or the app is killed. The mensagens are sent once the device is turned or and the app open.