Xperia Z Notification LED isn't working

Hi all,

I have the problem that my notification LED is not working at all.
Stamina mode is not on, the phone has been rebooted, i tried a factory reset.

Gmail, missed calls, Whatsapp i dont see any notification led only wenn charging.

Any1 a tip for me what todo?

Thanks

Dennis

WARNING!!!  DO NOT CHANGE COLORS IN Whats app.. the notification problem will again occur. i dont have any notifications since i changed the group notifications to purple in whatsapp.
Correct Answer by giocorrado  on Mar 4, 2013 10:31 AM

1 go to Settings - back up and restore - untick Backup my data and Auto restore
2 reset the phone
3 once the phone is switched on fallow the wizard installation
But do not back up ur data install everything manually...
Send ur self sms mail or whats app messages and the lights works
See the answer in context

http://talk.sonymobile.com/thread/120139