Why has my Android phone stop updating calendars, mail etc?

Try this: Go to settings ==> apps Find yor mail app Force it to stop Deactivate Reactivate Find your the mail amongst all your other apps and setup your mail account once more. Your gmail settings do not need to be set up again. Add the app to your homescreen again.

I do not know why it stopped working or if there is an easier solution, but this worked for me....:-)

Another possible cause: is your phone's memory full? If your phone is low on free memory, it will not sync any new data to it. You'll have to uninstall some apps or move them to the SD card to resolve this.

Go to Settings -> Accounts and sync:

1. Ensure Auto-sync is checked.
2. Check the relevant accounts to see if sync is enabled for them (click the account and see what's checked off).