Homebridge - problem authenticating with SmartThings

I am trying to install homebridge on my mac mini. I have created the SmartApp in Smartthings and if I go to the JSON API smartApp in the smartthings app on my iphone, I am able to select the switches.

when I tap on Done, it says it is installed and automating, but

Every time you add a device in the Smartthings app, you need to stop Homebridge on your Mac mini and restart Homebridge.

Make sureyou are copying and pasting credentials from the JSON smartapp on your phone not the API console

My homebridge config works fine so far - BUT when I reboot my Raspberry Pi, the App Id and the Access Token changes :frowning:

Any idea what I need to do to keep it static??