web request program generating web exception

using System;
using System.Collections.Generic;
//using System.Linq;
using System.Net;
using System.IO;
using System.Text;

namespace webrequest_demo.System.Net
{
    public class webrequestExample
    {
        public static void Main(String[] args)
        {
            try
            {

                WebRequest webr = WebRequest.Create(" "http://www.contoso.com/default.html"");
                webr.Credentials = CredentialCache.DefaultCredentials;
                WebResponse webresp = webr.GetResponse();
                Console.WriteLine(((HttpWebResponse)webresp).StatusDescription);
                Stream ds = webresp.GetResponseStream();
                StreamReader str = new StreamReader(ds);
                string responseFrommServer = str.ReadToEnd();
                str.Close();
                webresp.Close();

            }
            catch (WebException wex)
            {
                Console.WriteLine(wex.Message);
                Console.WriteLine(wex.Response);
                Console.WriteLine(wex.StackTrace);
                Console.WriteLine(wex.InnerException);
            }
            //finally
            //{


            //}

            Console.ReadLine();
        }
    }
}