405 method not allowed for web api 2 POST method

Question

I created the simplest WebAPI 2 application using empty project template and Web API folder structure (in Visual Studio 2013). And cannot make work post request.

This is my controller

public class XmlFileController : ApiController
{
    public IHttpActionResult Post(string payload)
    {
        return Ok();
    }

    public string Get()
    {
        return "Hello world";
    }
}

I didn't change the Routes or anything. To my understanding, routing should work by name convention.

When calling GET http://localhost:51356/api/XmlFile, I get back Status 200 OK.

When calling POST http://localhost:51356/api/XmlFile with string payload and Content-Type text/plain, I got back Status 405 Method Not Allowed.

What am I missing here? Thanks.

UPDATE: The routing configuration is as follows:

public static void Register(HttpConfiguration config)
    {
        // Web API configuration and services

        // Web API routes
        config.MapHttpAttributeRoutes();

        config.Routes.MapHttpRoute(
            name: "DefaultApi",
            routeTemplate: "api/{controller}/{id}",
            defaults: new { id = RouteParameter.Optional }
        );
    }

Answer 1

Your POST is expecting a parameter - payload in query string. Without this parameter, it is looking for Post() function which is not defined, hence you are getting 405 error.