I can got access code use 'Alexa Client Id' of skill account link page with 'profile alexa::skills:account_linking' scope. When I use the code to get the token, it return 400: {"error_description":"The authorization grant type is not supported by the authorization server","error":"unsupported_grant_type"}.
POST /auth/o2/token HTTP/1.1
Host: api.amazon.com
grant_type=authorization_code
&code=<the code>
&client_id=<'Alexa Client Id' of skill account link page>
&client_secret=<'Alexa Client Secret' of skill account link page>
&redirect_uri=<my RedirectUri same as the get code>
If I use 'Your Client ID' of skill account link page to get the code, then return "An unknown scope was requested."
