First of all, really appreciate your response. This is the first time that I'm working with Jquery Data-tables. JS along with JSON works perfectly in Test Environment. Can u plz explain data-table and its usage bcz I dont have much idea how to manipulate Jquery code.

I'm fetching client records from the database and after concatenating the model class properties(FirstName and LastName) I converted these records in JSON string. My goal is to display these records in Jquery Datatable. I observed at debugging, all these records are in a single string causing the error "Requested unknown parameter".

At first, I tried to return a simple JSON return method return Json(ClientList) but it did not concatenate the model class properties.
Thus, I used JsonConvert.SerializeObject() to convert all the details by passing ClientList object and now scratching my head how to use this JSON String in Jquery Datatable as all the records are in the following format :
[{\"Id\":1,\"FirstName\":\"abc\",\"LastName\":\"xyz\",\"FullName\":\"abc xyz\"},{\"Id\":2,\"FirstName\":\"qwe\",\"LastName\":\"rty\",\"FullName\":\"qwe rty\"}]
Model Class:

public string FirstName { get; set; }
public string LastName { get; set; }
public string FullName
                return FirstName + " " + LastName;


public ActionResult GetClientList()
            var ClientList = _context.Clients.ToList();
            //return Json(ClientList);

            string jsonData = JsonConvert.SerializeObject(clientList);
            return Json(jsonData);


        $(document).ready(function () {
                "ajax": {
                    "url": "/Client/GetClientList",
                    "type": "GET",
                    "datatype": "json",
                    "dataSrc": ""
                        { "data": "Id" },
                        { "data": "FullName" }