[Solved] ASP.Net jQuery Ajax Error: Undefined response

Hello,

I am using List (of T) in webservice to populate data from sql database into html table using ajax call.

I works perfectly but i get error undefined when the populating data exceed 301.

<script type="text/javascript">
   $(function () {
       $.ajax({
           type: "POST",
           url: "frmStudentList.aspx/GetStudentList",
           data: '{}',
           contentType: "application/json; charset=utf-8",
           dataType: "json",
           success: function (response) { alert(response.d); },
           failure: function (response) { alert(response.d); },
           error: function (response) { alert(response.d); }
       });
   });
     
   function OnSuccess(response) {
       $(function () {
           $('[id*=gvCustomers]').prepend($("<thead></thead>").append($(this).find("tr:first"))).DataTable({
               "responsive": true, "lengthChange": true, "autoWidth": false,
               "sLoadingRecords": {"loadingRecords": "Please wait - loading..."},
               lengthMenu: [[10, 20, -1], [10, 20, "All"]],
               "buttons": ["copy", "excel", "pdf", "print"],
               data: response.d,
               columns: [
                 { 'data': 'STUDENT_ID' },
                 { 'data': 'FULL_NAME' },
                 { 'data': 'GENDER' },
                 { 'data': 'PROGRAME' },
                 { 'data': 'FORM' },
                 { 'data': null, title: 'Edit', wrap: true, "render": function (item) { return '<div class="btn-group"> <button type="button" onclick="fnEdit(' + item.STUDENT_ID + ')"  class="btn btn-block btn-success btn-xs"><i class="fas fa-pencil-alt"></i> Edit</button></div>' } },
                 { 'data': null, title: 'Deactivate', wrap: true, "render": function (item) { return '<div class="btn-group"> <button type="button" onclick="fnDelete(' + item.STUDENT_ID + ')" class="btn btn-block btn-danger btn-xs"><i class="fas fa-trash"></i> Deactivate</button></div>' } },
                 ]
           }).buttons().container().appendTo('[id*=gvCustomers_wrapper] .col-md-6:eq(0)');
       });
   };

<WebMethod()> _
Public Shared Function GetStudentList() As List(Of STD)
    Dim strConnString As String = ConfigurationManager.ConnectionStrings("conString").ConnectionString
    Using con As New SqlConnection(strConnString)
        Using cmd As New SqlCommand("SELECT TOP 5 *  FROM STUDENT_RECORD ORDER BY FULL_NAME", con)
 
            Dim STDs As New List(Of STD)()
            con.Open()
            Using sdr As SqlDataReader = cmd.ExecuteReader()
                While sdr.Read()
                    STDs.Add(New STD() With { _
                        .STUDENT_ID = sdr("STUDENT_ID").ToString(), _
                        .FULL_NAME = sdr("FULL_NAME").ToString(), _
                        .GENDER = sdr("GENDER").ToString(), _
                        .PROGRAME = sdr("PROGRAME").ToString(), _
                    .FORM = sdr("FORM").ToString() _
                    })
                End While
            End Using
            Return STDs
            con.Close()
        End Using
    End Using
End Function
 
Public Class STD
    Public Property STUDENT_ID() As String
    Public Property FULL_NAME() As String
    Public Property GENDER() As String
    Public Property PROGRAME() As String
    Public Property FORM() As String
End Class