chat notification using onCreate trigger not working in firebase

[Aakash1]

I am just creating a onCreate trigger in firebase and it is not working for me.

const admin = require("firebase-admin");

const functions = require('firebase-functions');

var serviceAccount = require("./abc.json");

admin.initializeApp({ credential: admin.credential.cert(serviceAccount), databaseURL: "https://PROJECT_ID.firebaseio.com" });

exports.sendNotifications = functions.firestore .document('messages/{messageId}') .onCreate((snapshot, context) => { functions.logger.debug('This is a test'); })

and this function is successfully deployed and worked when i test it but not trigger automatically when new messageId is created.

I also try many other triggers like onWrite, onDelete etc but no one automatically invoke when data change.

please help and thanks in advance.

I want that it trigger automatically when new chat message come so that i can send chat notification to second person.