Authorization code grant

Hi,

I am following "1.2.1 Authorization code grant" from the doc http://topliners.eloqua.com/docs/DOC-5796

1) Get authorization code (Working)

2) To obtain access token and refresh token using POST request to login.eloqua.com/outh2/token endpoint.

For HTTP basic authentication I tried multiple options

a)Base64 encoded value "<company_name>\<client_identifier>:<client_secret>"

b)Base64 encoded value "<company_name>\<username>:<password>"

When I hit POST request always returning below error.

{

  error: "invalid_client"

  error_description: "The client is invalid or was not supplied with basic authentication."

}

Thanks,

Jason