Push notifications via firebase


I am implementing the custom push notifications for mobile app using google firebase for ios and android.

Steps for registering android app with sugar sdk:-
- Project created in firebase for android
- google-services.json file placed in the root directory of the android app in platform folder

The steps working on any other app but Notification is not appearing on SugarCRM app.

Please help and confirm what could be the issue and is there any other things to do this?