Could you plase share your push logs from the AppHQ dashboard?
To get the logs:
-Login to AppHQ
-Select Unified Notifications from the left most menu
-Select Push in the middle pane
-Select Logs from the Menu Icons under Push Notification header
You will find the push logs there. If there is no logs then please enable Push Log State from App Manager-> Settings -> Enable under Push Logs State.
It will really help to debug the issue.