Which service is responsible for syncing app data? On my phone (KitKat) it doesn't sync any more. The error is:
"Sync is currently experiencing problems. It will be back shortly."
Last sync was on 3 months ago. Other synchronized items (contacts, calendar, gmail, chrome) are still working. I tried to remove Google account and add it again, but it didn't help.
I know that restoring factory defaults fixes similar issues, but it's not the right solution since we do not know the root cause of the problem.