Calendar app won't sync to Google calendar

[AC Question]

Cannot get any calendar app to sync properly with Google calendar. Events created on the phone will sync to the online calendar. Events created online do not sync to the phone. I have tried the Samsung calendar app, the Google calendar app, and now aCalendar. Same issue with all of them.

I have tried:
- Uninstalling and reinstalling.
- Clearing data and turning sync on and off.
- Checking and unchecking the various accounts in different configurations.

Basically, I've tried all of the fixes that I have found in the various forums. No success.