Configure the add-on:
Settings -> API -> Enable personal API keys = ENABLED
Settings -> API -> API Key = BLANK/EMPTY
Settings -> API -> API Id = BLANK/EMPTY
Settings -> API -> API Secret = BLANK/EMPTY
Enable the api configuration page, to enable this go to the Settings - API and enable Enable API configuration page
You should then be able to update your keys by visiting http://<IP of Kodi device>:<port>/api
The port used is Settings - HTTP Server - Port which by default is 50152