Can't able to access the web servie? what is the problem

public static string web Request(string AuthoUserName, string AuthoPassword, string sUserID, string sUserName, string sPlateNo, string sPlateCat, string sPlateCode, string sEmirate, string sCountry, string sCity, string sChessisNo, string sFetchURL)
{
    string str = string.Empty;
    try
    {
        Uri requestUri = new Uri(sFetchURL);
        if (!(requestUri.Scheme == Uri.UriSchemeHttp))
        {
            return str;
        }
        HttpWebRequest request = null;
        request = (HttpWebRequest) WebRequest.Create(requestUri);
        request.Method = "GET";
        request.ContentType = "text/xml;charset=\"utf-8\"";
        string str2 = "<soapenv:envelope xmlns:soapenv="\"http://schemas.xmlsoap.org/soap/envelope/\"" xmlns:ae="\"http://ae.gov.trf.inq.ws.TrafficInquiryService\""><soapenv:header><ae:password>" + AuthoPassword + "</ae:password><ae:username>" + AuthoUserName + "</ae:username></soapenv:header><soapenv:body><ae:getvehicledetails><getvehicledetailsrequest><userid>" + sUserID + "</userid><username>" + sUserName + "</username><plate><plateno>" + sPlateNo + "</plateno><platecategory>" + sPlateCat + "</platecategory><platecode>" + sPlateCode + "</platecode><platesource><emirate>" + sEmirate + "</emirate><country>" + sCountry + "</country><city>" + sCity + "</city></platesource></plate><chassisno>" + sChessisNo + "</chassisno></getvehicledetailsrequest></ae:getvehicledetails></soapenv:body></soapenv:envelope>";
        request.Method = "POST";
        request.ContentType = "application/soap+xml; charset=utf-8";
        request.Headers.Add("SOAPAction:\"\"");
        request.ContentLength = str2.Length;
        StreamWriter writer = new StreamWriter(request.GetRequestStream());
        writer.Write(str2);
        writer.Close();
        StreamReader reader = new StreamReader(request.GetResponse().GetResponseStream());
        while (!reader.EndOfStream)
        {
            str = str + reader.ReadLine();
        }
    }
    catch (WebException exception)
    {
        HttpWebResponse response = null;
        response = (HttpWebResponse) exception.Response;
        StreamReader reader2 = new StreamReader(response.GetResponseStream());
        while (!reader2.EndOfStream)
        {
            str = str + reader2.ReadLine();
        }
    }
    return str;
}