If you're not receiving email and app notifications, follow these steps to check your account sync settings.
Frequent account synchronization can have a negative impact on battery life.
From a Home screen, navigate: Apps icon > Settings > Accounts & sync.
Tap the account.
Tap Account sync.
Tap the applicable switch(es) (e.g., App Data, Calendar, Contacts, etc.) to turn the sync settings on or off .
The settings presented vary depending upon account type.
To turn on master sync for all account types:
Navigate: Apps icon > Settings > Accounts and sync.