If you experience problems with Google Calendar sync, please make sure to have the latest Google Calendar app installed from Google Play. (Early versions of Android included a Google Calendar sync adapter, but this was moved to the Google Calendar app, to be able to update via Google Play.)
Test if synchronization works when you open the Google Calendar app. If it is working (the Google Calendar app synchronizes only in the foreground) this is a clear sign for background data/process limitations in Android.
The setting to turn on background data for the Google Calendar is different for Android versions and manufacturers. Mostly it is in the device settings under Data Usage or in the app info for the Google Calendar app.
If (background) data is switched on for the Google Calendar and sync is still not working, please check your:
- Google account settings under (this may vary!) device settings / accounts / Your google account / account synchronization / calendar
- energy saving options
- global sync settings in Android
aCalendar is not involved in synchronization, it is a user interface to the Android calendar storage.
Please also see the General Sync Issues / Sync of two devices page.