ติดปัญหาใช้ Ajax(jsonp) เรียก Webservice คับ รบกวนผู้รู้ช่วยทีคับ

 $.ajax({
                    type: 'POST',       
                    url :"http://192.168.1.81:8081/Service/Service/WebService.asmx/Register",
                    data: "PhoneNo="+PhoneNumber+"&RegID="+RegisID+"",  
                    dataType: "jsonp",
                    cache: false,
                    crossDomain: true,
                     success: function(callback){   
                              alert(callback);
                              
                      },
                        error:function(err){
                        alert("Error: "+ err.message + err.code);
                       }      
         
         });          

  [WebMethod]
        [ScriptMethod(ResponseFormat = ResponseFormat.Json, UseHttpGet = true)]//XmlSerializeString = false
        public void  Register(string PhoneNo, string RegID)
        {
            var con = new SqlConnection(Connection());
            con.Open();
            
            try
            {
                string Status = "รับข่าวสาร";
                var cmd = new SqlCommand("INSERT INTO tblRegister(PhoneNumber,RegID,Status,RegisterDate) values('" + PhoneNo + "','" + RegID + "','" + Status + "','" + DateTime.Now + "')", con);
                cmd.ExecuteNonQuery();
                var data = new { Phone= PhoneNo,Reg = RegID };
                JavaScriptSerializer serializer = new JavaScriptSerializer();
                string json = JsonConvert.SerializeObject(data, Formatting.Indented);
                json = StripControlChars(json);
               
                string output = Context.Request.Params["callback"];
                output += "(" + json + ");";	//System.Web.HttpUtility.HtmlEncode        
                
                Context.Response.ContentType = "application/json; charset=utf-8";
                Context.Response.Write("" + output+ "");
               
                              
            }
  }