If the synchronization doesn’t work between Google Calendar and GOrendezvous, follow these steps:
1. In your Gmail account, click your image in the top right corner of the page.
2. Then, click "Manage your google account"
2 - Click on "Connected apps & sites"
3 - Click on "Manage Apps"
4 - Click on the app GOrendezvous, and on "Remove".
5 - To finish, back to your GOrendezvous account and try again the synchronization. Please follow these steps.