Changes to Generate or refresh an access token

removed the media type text/plain for the response with the status 400

the response property error_description became optional for the status 500

added the new access_denied enum value to the error response property for the response status 500

added the new internal_server_error enum value to the error response property for the response status 500

added the new invalid_grant enum value to the error response property for the response status 500

added the new invalid_request enum value to the error response property for the response status 500

added the new not_found enum value to the error response property for the response status 500

added the new unauthorized enum value to the error response property for the response status 500

added the new unauthorized_client enum value to the error response property for the response status 500

added the media type application/json for the response with the status 400

added the optional property error_details to the response with the 500 status