Hi @krishnakanthpat
We have seen similar issues via the HTTP legacy protocol and moving it to HTTP v1 protocol, push notifications are now seen on Android devices...
I would say, don't bother debugging the legacy HTTP Android protocol, we're tried to put all the debug and there was nothing wrong on ACC side however the app wasn't receiving the notification no matter what
I can only encourage you to move to HTTP v1 instead, the support of HTTP v1 was introduced in release 9228 as seen in the release note (Oct. 2020) (https://experienceleague.adobe.com/docs/campaign-classic/using/release-notes/previous-releases/release--2020.html?lang=en#:~:text=process%20to%20crash.-,Release%2020.3.1%20%2D%20Build%209228,-October%2027%2C%202020)
I think since couple of months, Android might have stopped silently processing requests from the legacy protocol ...
Just migrate to HTTP v1 instead,
Thanks
Denis