The remote server returned an error: (403) Forbidden. while getting the website into stream reader

Question

I'm getting an error at

StreamReader stream = new StreamReader(request.GetResponse().GetResponseStream());

saying the remote server returned an error :

403 forbidden

I'm passing http://www.snapdeal.com in the URL.

StreamReader reader = objm.URLServerR(address);   
       public StreamReader URLServerR(string url)
                {
                    HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
                    StreamReader stream = new StreamReader(request.GetResponse().GetResponseStream());
                    return stream;
                }