This is the kicker - go back to the Apps Code, open Google SDM API, and click on OAuth in the top-right. This must be enabled in order to create the access token for handshaking and secure callbacks from Google for async events. Once enabled, you will need to remove and re-add the app, as the Hubitat token creation is only attempted during initial install, so as to not overwrite an in-use token.
Download the Hubitat app
