Google Calendar Writer Access Error

You need to have writer access to sync appointments to the selected Google Calendar. Please check with the Google Calendar owner in case syncing is required.

For Group Calendar:

For Unassigned Calendar:

Step 1:
The owner of the Google Calendar needs to be logged into Google and go to calendar.google.com.

Step 2:
Hover over the desired calendar, then click the three-dot icon and select "Settings and Sharing."

Step 3:
Scroll down to "Share with specific people" > Click "Add People" and add the email address of the Google Account that is synced in the platform > Set the permissions to "Make changes to events" > Click Send to save.

The Google Calendar should now be in sync with the platform.