Hello, I'm working on some code that does a simple database call and returns json data. I tested the webservice on my local machine and it returned the data fine. When I call the webservice from jQuery I get an error: 500 Internal Server Error. Here is my webservice: [WebMethod] [ScriptMethod(ResponseFormat = ResponseFormat.Json)] public string SignIn() { List<SignInCredentials> oList = new List<SignInCredentials>(); string queryString = "SELECT UserName, UserLastLogin FROM UserLogin;"; using (SqlConnection connection = new SqlConnection(ConfigurationManager.ConnectionStrings["MyConnection"].ToString())) { SqlCommand command = new SqlCommand(queryString, connection); connection.Open(); SqlDataReader reader = command.ExecuteReader(); // Call Read before accessing data. while (reader.Read()) { SignInCredentials sic = new SignInCredentials(); sic.Username = reader["UserName"].ToString(); sic.UserLastLogin = reader["UserLastLogin"].ToString(); oList.Add(sic); } // Call Close when done reading. reader.Close(); } // Return JSON data JavaScriptSerializer js = new JavaScriptSerializer(); string strJSON = js.Serialize(oList); return strJSON; } My AJAX call: $(document).ready(function () { $("#signIn").bind("click", function () { $("#signInSection").empty(); $("#signInSection").append('Sign In Status:'); $.ajax({ type: "POST", contentType: "application/json; charset=utf-8", url: "UserVerfication.asmx/SignIn", data: '{ }', dataType: "json", success: function (data) { $("#signInSection").append(data.UserName); }, error: function (jqXHR, textStatus, errorThrown) { alert(jqXHR + ":" + errorThrown); } }); }) }); Thanks for anything you can suggest.