Android GCM sent successfully but not received on some devices

1. Make sure you've set your SENDER ID you've received from Google correctly.
2. Make sure your device was registered with Google's GCM service correctly.
3. Make sure you are sending the push to the correct reg id you've received from Google. and that you didn't receive an error from Google GCM service.
4. Have you set the delay_while_idle = 1? This means the message won't reach the device if it's idle (off, offline, locked screen, etc...). Change it to delay_while_idle = 0 if you want your wakelock permission to make any difference. Please read more here.
5. Some times it takes time for the push to arrive (but never too much time, then there is a problem). Check what's the "time to live" of the push you've sent.

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.

if you are using wifi, may be the internet firewall block the gcm. try to use internet with your mobile sim card.

Checklist

• Make sure Google Play Store is updated to latest version
• Make sure there are no systemwide settings for notifications which are blocking
• Go into app in Application Manager and uncheck/recheck 'Notifications'
• If on Wifi, switch Wifi connection to a different AP (if possible)
• Reboot the device
• Install 'Push Notification Fixer' (install this anyway)

First-run notification setup can be annoyingly arbitrary and require the device be 'kicked' in one or more of these ways.