400 Bad request on c# code -

getting error exception thrown on small piece of code can't figure out why / where. new apprecaited

private void getservicedata(string url) {     try     {         if (!string.isnullorempty(this.service) && !string.isnullorempty(url))         {             string data = string.empty;             string name = string.format("{0}data", this.service);              using (webclient client = new webclient())             {                 data = client.downloadstring(url);             }              page.clientscript.registerhiddenfield(name, data);         }     }     catch (exception ex)     {         shared.utilities.exceptionlog.writeexceptiontolog(ex, "coursefinderservicecontrol.getservicedata()");     } } 

if twitch, need specify client when requesting data.