network credential cannot pass to webservice

Hi all,

      I'm trying to my network credential  pass to my web page and web service, i got this error "the request fail with http status 403: forbidden.". But when i open from IIS it can be open(Right Click Browse). So that, i try with window application same code of web. Those application also can get data. And then i open that application from other machine. All can get data from my database server.
What wrong iis or my code .... ?

Here is my sample code :
        Label1.Text = HttpContext.Current.User.Identity.Name.ToString();
        navserv.Units_of_Measure_Service _ws = new navserv.Units_of_Measure_Service();
        _ws.Url = "http://192.168.0.98:7047/DynamicsNAV/WS/Cronus/Page/Units_of_Measure";  ...