Custom API handler

I am trying to create a simple api handler as part of a customization

using System.Collections.Generic;
using System.IO;
using System.Web;
using Newtonsoft.Json;

namespace SampleAPI
{


    public class SampleApiHandler : IHttpHandler
    {
        public bool IsReusable => false;

        public void ProcessRequest(HttpContext context)
        {
            context.Response.ContentType = "application/json";
    context.Response.Write("{\"status\":\"ok\"}");
        }
    }
}

I published the customization and changed web.config

 

 <add name="SampleAPI"
       path="api/sampleApi"
       verb="POST"
       type="SampleAPI.SampleAPIHandler"
       resourceType="Unspecified"
       preCondition="integratedMode" />

But I am not able to call it, it times out, am I doing anything wrong?