I am using a Samsung Galaxy S10 mobile. On February 3rd Security patch was updated on my phone. After the update Push notification was not received in my App. Other App notifications are working fine. Anyone can answer my question, please? What was the reason for not receiving notification?
The answer could be because the PendingIntent for that app's notifications hasn't had its mutability defined. Starting from Android 12, you have to define whether a PendingIntent is immutable or mutable for it to work properly:
https://developer.android.com/about/versions/12/behavior-changes-12#pending-intent-mutability
Another thing to try to make notifications work again is to add the "exported:false" tag to the notifications service:
https://developer.android.com/about/versions/12/behavior-changes-12#exported
That should help.