Failure to display push notification could be due to various reasons. The most common case is the application has NOT enabled push notification on the device. You could enable this by going into Settings > Notifications on the device. If the notifications are enabled, you could try and install the application on another device to see if the notification goes through as expected. This will help to narrow down the scope of the issue to be either device specific or application specific.

Further, you can also connect the mobile phone with the debugger (or IDE) and check if the push notification arrives at the device but for some reason fails to display the notification.

Don’t forget to configure the message delivery status attributes. If you do so, log entries will be sent to CloudWatch Logs for messages sent to a topic subscribed to an Amazon SNS endpoint, which helps to know whether a message was delivered to the Amazon SNS endpoint etc.

In addition, you can use X-Ray with Amazon SNS to trace and analyze the messages that travel through your application. AWS X-Ray collects data about requests that your application serves, and lets you view and filter data to identify potential issues and opportunities for optimization.