$corvovaPushV5 registering but not firing onNotification

I am trying to implement push notifications in Ionic V1 using $cordovaPushV5 but I am not able to get to work. I am able to get the device registration ID but when I test notifications using Firebase Cloud Messaging, it doesnt work. Below is app.js code -


FCM screenshot -

I followed the below link to implement -

What am I missing ?