oauthenticator.auth0.Auth0OAuthenticator don't send authorization_code

JupyterHub
1

Hello,
I’m trying to configure Jupyterhub to authentify and authorize users using the OpenID Connect provider of my company.
To do that I defined the following variables in the jupyter_config.py :

              c.JupyterHub.authenticator_class = 'oauthenticator.auth0.Auth0OAuthenticator'
              c.Auth0OAuthenticator.auth0_domain =  ...
              c.Auth0OAuthenticator.oauth_callback_url = ...
              c.Auth0OAuthenticator.client_id = ...
              c.Auth0OAuthenticator.client_secret = ...
              c.Auth0OAuthenticator.scope =  ...
              c.Auth0OAuthenticator.authorize_url = ...
              c.Auth0OAuthenticator.token_url = ...

However I get an error 500: Internal Server Error.
The logs indicates the following error:

    { "error": "invalid_request",
     "error_description": "Missing grant_type parameter"    }

It appears “grant_type: authorization_code” is not send as a POST parameter while calling the token_url.
Also I tryied to force it using this:
c.Auth0OAuthenticator.token_params = {"grant_type": "authorization_code"}

Unfortunately nothing changed. Grant_type is still not send.
Any idea how to do ?