Android GCM sent successfully but not received on some devices

Question

On the server side, I am using GCM server 1.0.2 library provided by Google. On the client side, I set up GCM as provided on the official documentation.

My problem is

Answer 1

Do you have the correct version of the Playstore to receive the notification ? Are you logged with a functional Google Account on those devices ?

I also had a problem when I "Force stop" an app, you can't receive notification on any app after a "force stop" (start with android 3.1) so be careful with that too.