c# - Bad Request 400 - protocol error on a valid url - Webclient -

i trying parse page (http://www.coleparmer.co.uk/product/turb_std_hach_2100q_kit/wz-99900-47) using webclient , having no luck.

 var client = new webclient();   var html = client.downloadstring("http://www.coleparmer.co.uk/product/turb_std_hach_2100q_kit/wz-99900-47"); 

the appropriate headers needs set.

try {     string html;     using (webclient client = new webclient())     {         client.headers.add("accept-language", " en-us");         client.headers.add("accept", " text/html, application/xhtml+xml, */*");         client.headers.add("user-agent", "mozilla/5.0 (compatible; msie 9.0; windows nt 6.1; trident/5.0)");         html = client.downloadstring("http://www.coleparmer.co.uk/product/turb_std_hach_2100q_kit/wz-99900-47");     } } catch (webexception ex) {     if (ex.status == webexceptionstatus.protocolerror && ex.response != null)     {         var resp = (httpwebresponse)ex.response;         if (resp.statuscode == httpstatuscode.notfound) // http 404         {             //handle         }     }     //handle }