The remote server returned an error: (503) Server Unavailable.

protected void btn_Click(object sender, EventArgs e)
    {
        try
        {
 
            send("way2sms_userid", "way2sms_password", txtxmsg.Text, txtphn.Text);
            Response.Write("message send successfully......");
        }
        catch
        {
            Response.Write("Error Occured!!!");
        }
    }
    public void send(string uid, string password, string message, string no)
    {
        HttpWebRequest myReq = (HttpWebRequest)WebRequest.Create("http://ubaid.tk/sms/sms.aspx?uid=" + uid + "&pwd=" + password + "&msg=" + message + "&phone=" + no + "&provider=way2sms");
        HttpWebResponse myResp = (HttpWebResponse)myReq.GetResponse();
        System.IO.StreamReader respStreamReader = new System.IO.StreamReader(myResp.GetResponseStream());
        string responseString = respStreamReader.ReadToEnd();
        respStreamReader.Close();
        myResp.Close();
    }