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

[HttpPost] is unnecessary!

[Route("")]
public void Post(ProductModel data)
{
    ...
}

Answer 2

You are POSTing from the client:

await client.PostAsJsonAsync("api/products", product);

not PUTing.

Your Web API method accepts only PUT requests.

So:

await client.PutAsJsonAsync("api/products", product);

Answer 3

My problem turned out to be Attribute Routing in WebAPI. I created a custom route, and it treated it like a GET instead of WebAPI discovering it was a POST

    [Route("")]
    [HttpPost] //I added this attribute explicitly, and it worked
    public void Post(ProductModel data)
    {
        ...
    }

I knew it had to be something silly (that consumes your entire day)

Answer 4

check in your project .csproj file and change

<IISUrl>http://localhost:PORT/</IISUrl>

to your website url like this

<IISUrl>http://example.com:applicationName/</IISUrl>

Answer 5

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:

<httpProtocol>
    <customHeaders>
        <clear />
        <add name="Access-Control-Expose-Headers " value="WWW-Authenticate"/>
        <add name="Access-Control-Allow-Origin" value="*" />
        <add name="Access-Control-Allow-Methods" value="GET, POST, OPTIONS, PUT, PATCH, DELETE" />
        <add name="Access-Control-Allow-Headers" value="accept, authorization, Content-Type" />
        <remove name="X-Powered-By" />
    </customHeaders>
</httpProtocol>

Answer 6

Make sure your controller inherits from Controller class.

It might even be crazier that stuff would work locally even without that.