Access Token Request
The client makes a request to the token endpoint by adding the following parameters using
            the application/x-www-form-urlencoded format with a character encoding
            of UTF-8 in the HTTP request entity-body. The limitation is that no refresh token will
            be issued according to OAuth 2.0 specs.
| Token | Option | Description | 
|---|---|---|
grant_type | 
                        REQUIRED | Value MUST be set to client_credentials. |