trying to implement auth according to the auth API: https://developers.home-assistant.io/docs/en/auth_api.html
i do the auth step where i authenticate with home assistant via username/password, and then HA redirects to my app with a code.
http://localhost:8000/auth/callback?code=16f9ed5ebb744bbd95e8f89c3e193f62
then, as per the docs, i send a POST request http://localhost:8123/auth/token?grant_type=authorization_code&code=16f9ed5ebb744bbd95e8f89c3e193f62&client_id=http%3A%2F%2Flocalhost:8000
but i get a response from HA, a 400 error {"error": "unsupported_grant_type"}
do i need to configure supported grant_type somewhere? am i missing something? i’m using the grant_type=authorization_code as per the docs, so i don’t understand why i’m getting this error.