HTTP API help

I have worked through the HTTP API and can’t get authorization to work.

Here’s the device preferences:

	section("Allow Endpoint to Control These Things...") {
		input "sensors", "capability.contactSensor", title: "Which Sensors?", multiple: true
        input "relays", "capability.polling", title: "Which Relays?", multiple: true
	}

Here’s the mappings:

mappings {
 
	path("/sensors") {
		action: [
			GET: "listSensors"
		]
	}
	path("/sensors/:id") {
		action: [
			GET: "showSensor"
		]
	}
	path("/sensors/:id/:command") {
		action: [
			GET: "updateSensor"
		]
	}
	path("/relays") {
		action: [
			GET: "listRelays"
		]
	}
	path("/relays/:id") {
		action: [
			GET: "showRelay"
		]
	}
	path("/relays/:id/:command") {
		action: [
			GET: "updateRelay"
		]
	}    
    
}

I made it through the OAuth and was returned my token, and was able to assemble this URL:

https://graph.api.smartthings.com/api/smartapps/installations/$Client_id/sensors?access_token=$token

This returns:
{"error":true,"type":"AccessDenied","message":"This request is not authorized by the specified access token"}

Note: I authorized these devices on the OAuth page

What did I miss?

Did you ever get this working? I would also like to have a third party application integrate with my ST devices and I am getting the same error. I have been through the documentation and don’t understand how to get the Authorization Code since it requires you to choose the device in the GUI. I was expecting to use the same code each time to get the token.

Thanks!