Authorization via ASP.NET Web API in Orchard CMS

Creating an ASP.NET Web API module in Orchard CMS is simple and straightforward. The following link explains how to do this, and everything works fine. http://www.sebastienros.com/web-api-makes-it-in-orchard

However, GET requests do not work when the WebAPI is running under Orchard and you are using the attribute at the same time [Authorize].

  [Authorize]
  public IEnumerable<string> Get()
  {
    return _moduleManager.GetUsers().Select(n => n.UserName);
  }

When I call it from the client

HttpClientHandler handler = new HttpClientHandler();
handler.Credentials = new NetworkCredential("user", "password");            
HttpClient client = new HttpClient(handler);
var response = await client.GetAsync("http://localhost:30321/OrchardLocal/api/MyWebAPIModule/Users");
Console.WriteLine(response);

the variable responsereturns me an “Not Found” HTML page from Orchard. Without [Authorize]it, it returns a list of users.

Does Orchard have something built-in to match credentials with a registered user in Orchard? Or are there no steps in this process?