405 method not allowed Web API

Question

This error is very common, and I tried all of the solutions and non of them worked. I have disabled WebDAV publishing in control panel and added this to my web config file:<

Answer 1

I could NOT solve this. I had CORS enabled and working as long as the POST returned void (ASP.NET 4.0 - WEBAPI 1). When I tried to return a HttpResponseMessage, I started getting the HTTP 405 response.

Based on Llad's response above, I took a look at my own references.

I had the attribute [System.Web.Mvc.HttpPost] listed above my POST method.

I changed this to use:

[System.Web.Http.HttpPostAttribute]
[HttpOptions]
public HttpResponseMessage Post(object json)        
{
    ...
    return new HttpResponseMessage { StatusCode = HttpStatusCode.OK };
}

This fixed my woes. I hope this helps someone else.

For the sake of completeness, I had the following in my web.config: