Can not get Ticket.

Before i could access and got Ticket. but now i can not get ticket and error occured instead.
error message is "can not connect remote server." .
this error message was written in our countries language. so i translated it into english.

my program to get ticket is the following
this error occured when Thread executed [req.GetRequestStream();]
please help me....

       private string GetTicket(string service, string userId, string password)
        {
            string strTicket = null;

            try {

                string url = "https://accounts.zoho.com/login";
                byte[] data = Encoding.ASCII.GetBytes("servicename=" + service
                    + "&FROM_AGENT=true&LOGIN_ID="+userId
                    +"&PASSWORD=" + password);

                HttpWebRequest req = (HttpWebRequest)WebRequest.Create(url);
                req.Method = "POST";
                req.ContentType = "application/x-www-form-urlencoded";
                req.ContentLength = data.Length;

                Stream reqStream = req.GetRequestStream();
                reqStream.Write(data, 0, data.Length);
                reqStream.Close();