How to call ASP.NET jQuery Ajax function from CodeFile Method ["website Project"]

Question

I'm calling the ajax function using javascript in website project and the webmethod aspx page is running on CodeFile="NewPLPage.aspx.cs" and when I run the NewPLPage.aspx page I'm getting the following error

Error is :

Uncaught TypeError: Cannot read properties of undefined (reading '0')
Screenshot

website project example pic
Screenshot

I'm not sure where I did the mistake in the code

this my aspx code "NewPLPage.aspx" :

<figure class="highcharts-figure">
     <div id="container"></div>
</figure>

javascript code :

$(document).ready(function () {

 linedata();

}

function linedata() {
    //var param = "Line";
    var param = { Terms: $('#portperfgrphtab6M').text() };
    $.ajax({
        type: "POST",
        contentType: "application/json; charset=utf-8",
        data: JSON.stringify(param),
        url: "NewPLPage.aspx/GetLineChartData",
        dataType: "json",

        success: function (Result) {
            Result = Result.d;
            var data = [];
            for (var i in Result) {
                //var serie = new Array(Result[i].Names, Result[i].Values, Result[i].Dummy);
                var serie = new Array(Result[i].Date, Result[i].Niftyperform, Result[i].Portfolioperform);
                data.push(serie);
            }

            DreawLineChart(data);

            $(".highcharts-credits")[0].innerHTML = "";
            $(".highcharts-button-symbol").hide();
        },
        error: function (Result) {
            alert("Something Went Wrong !");
        }
    });
}

/*Inter link of "linedata()"*/
function DreawLineChart(series) {

    Highcharts.chart('container', {
        chart: {
            type: 'line'
        },
        title: {
            text: 'Performance Graph'
        },
        //subtitle: {
        //    text: 'Source: WorldClimate.com'
        //},

        xAxis: {
            //categories: ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun',
            //    'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec']

            categories: [series[0][0], series[1][0], series[2][0], series[3][0], series[4][0], series[5][0]] // Getting error : Uncaught TypeError: Cannot read properties of undefined (reading '0')

        },
        yAxis: {
            title: {
                text: ''
            },
            //labels: {
            //    formatter: function () {
            //        return this.value + '°';
            //    }
            //}
        },
        tooltip: {
            crosshairs: true,
            shared: true
        },
        plotOptions: {
            line: {
                marker: {
                    radius: 4,
                    lineColor: '#666666',
                    lineWidth: 1,
                }
            }
        },
        series: [{
            name: 'NiftyPerform',
            marker: {
                symbol: 'diamond'
            },
            //data: [7.0, 6.9, 9.5, 14.5, 18.2, 21.5, 25.2, {
            //    y: 26.5,
            //    marker: {
            //        symbol: 'url(https://www.highcharts.com/samples/graphics/sun.png)'
            //    }
            //}, 23.3, 18.3, 13.9, 9.6]

            data: [series[0][1], series[1][1], series[2][1], series[3][1], series[4][1], series[5][1]]

        }, {
            name: 'PortfolioPerform',
            marker: {
                symbol: 'diamond'
            },
            //data: [{
            //    y: 3.9,
            //    marker: {
            //        symbol: 'url(https://www.highcharts.com/samples/graphics/snow.png)'
            //    }
            //}, 4.2, 5.7, 8.5, 11.9, 15.2, 17.0, 16.6, 14.2, 10.3, 6.6, 4.8]
            data: [series[0][2], series[1][2], series[2][2], series[3][2], series[4][2], series[5][2]]
        }]
    });
}

this is NewPlPage.cs page code :

[WebMethod]
    public static List<Performgraph> GetLineChartData(string Terms)
    {

        //string Terms
        //string Terms = "";
        DataTable dt = new DataTable(); //null;
                                        //List<object> chartData = new List<object>();
                                        //List<string> reports = new List<string>();
        List<string> starttime = new List<string>();
        List<Performgraph> performgraphs = new List<Performgraph>();
  GetPerformgraphapp getPerformgraphapp = GraphData(); // Getting service data without any error


        if (Terms == "6M")
            dt = getPerformgraphapp.M6.ConvertToDataSet("Graph6M").Tables[0];
        else if (Terms == "1Y")
            dt = getPerformgraphapp.YR1.ConvertToDataSet("Graph1Y").Tables[0];
        else if (Terms == "2Y")
            dt = getPerformgraphapp.YR2.ConvertToDataSet("Graph2Y").Tables[0];
        else if (Terms == "3Y")
            dt = getPerformgraphapp.YR3.ConvertToDataSet("Graph3Y").Tables[0];
        else if (Terms == "5Y")
            dt = getPerformgraphapp.YR5.ConvertToDataSet("Graph5Y").Tables[0];


        if (dt.Rows.Count > 0 && dt != null)
        {

            ////Insert Label for columns in First position.
            //reports.Insert(0, "LineChart");
            //reports.Add("NiftyPerform");
            //reports.Add("PortfolioPerform");

            ////Add the columns Array to the Chart Array.
            //chartData.Add(reports.ToArray());

            starttime = (from p in dt.AsEnumerable()
                         select p.Field<string>("DATE")).ToList();

            string yyMMM = "";
            foreach (string datetime in starttime)
            {


                List<object> niftyperform = (from p in dt.AsEnumerable()
                                             where p.Field<string>("DATE") == datetime
                                             select p.Field<double>("niftyperform")).Cast<object>().ToList();


                //Should not use or convert the string data
                //List<object> totals = (from p in dt.AsEnumerable()
                //                       where p.Field<string>("DATE") == datetime
                //                       select Convert.ToString(p.Field<double>("portfolioperform"))).Cast<object>().ToList();

                List<object> portfolioperform = (from p in dt.AsEnumerable()
                                                 where p.Field<string>("DATE") == datetime
                                                 select p.Field<double>("portfolioperform")).Cast<object>().ToList();


                yyMMM = Convert.ToDateTime(datetime).ToString("yyMMM");
                //string[] yymmm = Convert.ToDateTime(datetime).GetDateTimeFormats();


                //totals.Insert(0, Convert.ToDouble(niftyperform[0]));
                //totals.Insert(0, yyMMM.ToUpper().ToString());
                //chartData.Add(portfolioperform.ToArray());

                performgraphs.Add(new Performgraph
                {
                    Date = yyMMM.ToUpper().ToString(),
                    Niftyperform = Convert.ToDouble(niftyperform[0]),
                    Portfolioperform = Convert.ToDouble(portfolioperform[0])
                });

            }

            //return chartData;
        }
        else
        {
            //Page page = (Page)HttpContext.Current.Handler;
            //Control myDiv = (Control)page.FindControl("pfperformchart");
        }

        return performgraphs;
    }

Class :

    public class Performgraph
    {
        public string Date { get; set; }
        public double Niftyperform { get; set; }
        public double Portfolioperform { get; set; }
    }

Give the best suggestion to resolve this error

I'm new to ajax call and webmethod concepts.