i used this code in .ashx  for upload pdf it fine when pdf size is less then 1 mb but if pdf file is larger than show error maxLimit

i used this code

<%@ WebHandler Language="C#" Class="pdfUploader" %>

using System;
using System.IO;
using System.Net;
using System.Web;
using System.Web.Script.Serialization;
using System.Drawing;
using System.Drawing.Drawing2D;

public class pdfUploader : IHttpHandler
{
    public void ProcessRequest(HttpContext context)
    {
        //Check if Request is to Upload the File.
        if (context.Request.Files.Count > 0)
        {
            //Fetch the Uploaded File.
            HttpPostedFile postedFile = context.Request.Files[0];

            //Set the File Name.
            string fileName = Path.GetFileName(postedFile.FileName);
            string extension = Path.GetExtension(fileName);
            if (extension.ToLower() != ".pdf")
            {
                string json2 = new JavaScriptSerializer().Serialize(
                new
                {
                    name = "Only PDF Format Accepted...",
                    name2 = "warning"
                });

                context.Response.StatusCode = (int)HttpStatusCode.OK;
                context.Response.ContentType = "text/json";
                context.Response.Write(json2);
                context.Response.End();
                return;
            }

            if (File.Exists(context.Server.MapPath("~/AdminPannel/UploadingPDF/") + fileName))
            {
                File.Delete(context.Server.MapPath("~/AdminPannel/UploadingPDF/" + fileName));
            }

            //save Pdf File into Folder
            string folderPath = context.Server.MapPath(@"~/AdminPannel/UploadingPDF/") + fileName;
            postedFile.SaveAs(folderPath);

            //Send File details in a JSON Response.
            string json = new JavaScriptSerializer().Serialize(
            new
            {
                name = fileName + " " + "Has been Uploaded SucessFully...",
                name2 = "success",
                name3 = fileName
            });

            context.Response.StatusCode = (int)HttpStatusCode.OK;
            context.Response.ContentType = "text/json";
            context.Response.Write(json);
            context.Response.End();
        }
    }

    public bool IsReusable
    {
        get
        {
            return false;
        }
    }
}