GEM TeslaApi::Client.new(access_token returns 406 - also can I create client with refresh_token?

[ConfusedAsHeck]

Ruby and Tesla_api newbie. When I use TeslaApi::Client.new(access_token.. with a token generated at https://tesla-info.com/tesla-token.php the server responds with a 406.

Also, in my confused newbie state, I wonder if there is a way to log in with the refresh_token using the GEM? Use it to get an access_token and then use the access_token to create the client maybe?