I"m trying to integrate Appointments + with a google

I"m trying to integrate Appointments + with a google business
account calendar. I've confirmed with google that our account is able to use the API and have it enabled and setup. However when testing the connection all I get is an error: Error calling POST https://www.googleapis.com/calendar/v3/calendars/beeherzpsychicmedium.com_24uagqtikh6ofk05tcp61nt5po@group.calendar.google.com/events: (404) Not Found