ASP.NET sends JSON data to HTTP API with authentication header

Question

I have C # code to send JSON data to the web API , but I keep getting a 401 response (unauthorized). The code below should correctly make a POST request according to this function , right? I also tried small variations with the same result.

This is the code that makes the request:

public async Task Create()
{
    using (var client = new HttpClient())
    {
        client.BaseAddress = new Uri("https://zrh.cloudsigma.com/api/2.0/");
        var testVM = new CS_VM("test");
        var auth = string.Format("{0}:{1}", "[e-mail]", "password");
        var encoded = Convert.ToBase64String(Encoding.ASCII.GetBytes(auth));
        client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Basic", encoded);

        HttpResponseMessage response = await client.PostAsJsonAsync("servers", testVM);
        if (response.IsSuccessStatusCode)
        {
            var a = "ok";
        }
        else
        {
            var a = "fail";
        }
    }
}

and this is a class that is dispatched as JSON:

public class CS_VM
{
    public CS_VM(string type)
    {
        if ("test" == type)
        {
            cpu = 1000;
            mem = 536870912;
            name = "testServer";
            vcn_password = "testserver";
        }
    }
    public string name { get; set; }
    public int cpu { get; set; }
    public int cores { get; set; }
    public int mem { get; set; }
    public string status { get; set; }
    public Owner owner { get; set; }
    public Uri resource_uri { get; set; }
    public string uuid { get; set; }
    public string vcn_password { get; set; }
}

Request Headers:

Authorization: Basic bWFpbEBtYWlsLmNvbTpwYXNzd29yZA==

And the response headers:

Transfer-Encoding: chunked
Connection: keep-alive
Vary: Cookie
X-REQUEST-ID: 2584e232-5bb2-48c0-a307-67e6c03258c0
Date: Sun, 19 Jul 2015 21:39:21 GMT
Server: cloudflare-nginx
WWW-Authenticate: Digest nonce="1437341961.55:6967:0fd0a6b2dcde8f45a5ae288c3b73ee12", realm="users", algorithm="MD5",opaque="b228739d1711b0ff025703aea82ee2a208faaaa7", qop="auth", stale="false", Basic Realm="users"
CF-RAY: 2089941a6935168e-ARN

Answer 1

WWW-Authenticate: Digest nonce="1437341... , . . , -API Digest Access Authentication. nonce, realm, qop 401.