Firebase Messaging with Django

I've been struggling for a long time. After hours and days I could see a light at the end of the tunnel.

I'm using a plugin for Django, this one: link

In my INDEX.HTML I have the following code:

<script src="https://www.gstatic.com/firebasejs/4.4.0/firebase.js"></script><script>//InitializeFirebasevarconfig={apiKey:"XXXXXX",
    authDomain: "XXXXXX",
    databaseURL: "XXXXX",
    projectId: "XXXXXX",
    storageBucket: "XXXXX",
    messagingSenderId: "XXXXXXX"
  };
  var app = firebase.initializeApp(config);
  var messaging = firebase.messaging(app);
  messaging.requestPermission()
.then(function() {
  console.log('Notification permission granted.');
  return messaging.getToken();
})
.then(function(token) {
  console.log(token); // Display user token
})
.catch(function(err) { // Happen if user deney permission
  console.log('Unable to get permission to notify.', err);
});

messaging.onMessage(function(payload){
        console.log('onMessage',payload);
})
</script>

I do not know where I'm going wrong, I've gone through the documentation, followed all the tutorials I've seen in Google results. It arrives to appear the TOKEN of the user, I arrive to send a message and appears in my devtools only a message:

Service Worker was updated because "Update on reload" was checked in the DevTools Application panel.

Every time I send a push this appears, but push does nothing at all. I added a device to this plugin that I'm using but it has a field I did not understand.

The Registration Token field I added the user generated token. There is another field called Device ID (Unique device identifier) . I left it blank because I do not know how to capture it.

Someone help me please? I would have to make Django work, do not roll a NodeJS no.

Thank you in advance.