Push Notification not showing if app is closed or device is locked

Hi there,
I am using your cloud service push for my app. Currently I am using Ionic 1.x. I set up my project to use push services as per the latest documentation (http://docs.ionic.io/services/push/).

The problem I am facing is the push notification is not working on the actual devices as it is working fine in Emulator. I have gone through many sites for the solution, But didn’t find anything or found solutions on the legacy API. Can anyone please help to resolve this issue? Am I missing something?