This tutorial will show you to connect your Google calendar to your HighLevel calendar if you are receiving the following 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.
The owner of the Google calendar needs to be logged into Google and go to calendar.google.com
Hover over the desired calendar then click the three dot icon and select "Settings And Sharing"
Scroll down to "Share with specific people" > Click "Add People" and add the email address of the Google Account that is synced in HighLevel > set the Permissions to "Make changes to events" > click Send to save
The Google calendar should now be in sync with HighLevel