i need help with indi.

This indicator does not work on the backtest, but it works on a live chart.

using System;
using cAlgo.API;
using cAlgo.API.Internals;
using cAlgo.API.Indicators;
using cAlgo.Indicators;
using System.Threading;
using System.Collections.Generic;
using System.Windows;

namespace cAlgo
{
    [Indicator(IsOverlay = false, TimeZone = TimeZones.UTC, AccessRights = AccessRights.None, ScalePrecision = 5, AutoRescale = true)]
    public class Indexator : Indicator
    {
        [Parameter("Master Currency", DefaultValue = "EURUSD")]
        public string masterName { get; set; }

        [Parameter("Slave Currency", DefaultValue = "AUDUSD")]
        public string slaveName { get; set; }

        [Parameter("TimeFrame")]
        public TimeFrame timeFrame { get; set; }

        [Parameter("Period", DefaultValue = 90, MinValue = 0, Step = 1)]
        public int Period { get; set; }

        [Parameter("Draw Chart", DefaultValue = true)]
        public bool drawChartz { get; set; }

        [Output("Index", LineColor = "Blue")]
        public IndicatorDataSeries Index { get; set; }

        private Bars masterBars;
        private Symbol masterSymbol;
        private Bars slaveBars;
        private Symbol slaveSymbol;
        public double backSlaveValue;
        public double PercentDiffrence;

        private ChartTrendLine masterLine;
        private ChartTrendLine slaveLine;
        private ChartTrendLine differenceLine;
        private ChartText masterNameChartText;
        private ChartText slaveNameChartText;
        private ChartText differenceChartText;

        public double masterMedianOut;
        public double slaveMedianOut;

        List<double> ResultClose = new List<double>();

        protected override void Initialize()
        {
            masterSymbol = Symbols.GetSymbol(masterName);
            masterBars = MarketData.GetBars(timeFrame, masterName);

            slaveSymbol = Symbols.GetSymbol(slaveName);
            slaveBars = MarketData.GetBars(timeFrame, slaveName);

            while (slaveBars.Count < Period * 2)
            {
                var loadedCount = slaveBars.LoadMoreHistory();
                if (loadedCount == 0)
                    break;
            }
            while (masterBars.Count < Period * 2)
            {
                var loadedCount = masterBars.LoadMoreHistory();
                if (loadedCount == 0)
                    break;
            }
        }

        public override void Calculate(int index)
        {
            if (index < Period * 2)
            {
                Index[index] = Double.NaN;
                return;
            }
            
            double masterSum = 0;
            double slaveSum = 0;

            for (int i = 0; i < Period; i++)
            {
                    var masterBarsIndex = masterBars.OpenTimes.GetIndexByTime(Bars.OpenTimes[index]) - i;

                    if (!double.IsNaN(masterBarsIndex))
                        masterSum = masterSum + masterBars[masterBarsIndex].Close;

                    var slaveBarsIndex = slaveBars.OpenTimes.GetIndexByTime(Bars.OpenTimes[index]) - i;

                    if (!double.IsNaN(slaveBarsIndex))
                        slaveSum = slaveSum + slaveBars[slaveBarsIndex].Close;             
            }
            

            var masterMedian = masterSum / Period;
            masterMedianOut = masterMedian;
            var slaveMedian = slaveSum / Period;
            slaveMedianOut = slaveMedian;

            double k = masterMedian / slaveMedian;

            var masterBarsIndexMain = masterBars.OpenTimes.GetIndexByTime(Bars.OpenTimes[index]);
            var slaveBarsIndexMain = slaveBars.OpenTimes.GetIndexByTime(Bars.OpenTimes[index]);

            ResultClose.Add(slaveBars.ClosePrices[slaveBarsIndexMain] * k);

            Index[index] = PercentDiffrence = (masterBars.ClosePrices[masterBarsIndexMain] - slaveBars.ClosePrices[slaveBarsIndexMain] * k) * 100 / masterBars.ClosePrices[masterBarsIndexMain];
            
          
            if (drawChartz == true)
            {
                if (Chart.FindObject("Point" + (Bars.ClosePrices.Count - 1000).ToString()) != null)
                    Chart.RemoveObject("Point" + (Bars.ClosePrices.Count - 1000).ToString());

                Chart.DrawTrendLine("Point" + (Bars.ClosePrices.Count - 1).ToString(), Bars.ClosePrices.Count - 2, ResultClose[ResultClose.Count -2], Bars.ClosePrices.Count - 1, ResultClose[ResultClose.Count - 1], "Blue", 2);

                masterLine = Chart.DrawTrendLine("MasterTool", index, masterBars.ClosePrices[masterBarsIndexMain], index + 20, masterBars.ClosePrices[masterBarsIndexMain], "Green");
                slaveLine = Chart.DrawTrendLine("SlaveTool", index, slaveBars.ClosePrices[slaveBarsIndexMain] * k, index + 20, slaveBars.ClosePrices[slaveBarsIndexMain] * k, "Green");
                differenceLine = Chart.DrawTrendLine("Difference", index + 15, masterBars.ClosePrices[masterBarsIndexMain], index + 15, slaveBars.ClosePrices[slaveBarsIndexMain] * k, "Green");
                masterNameChartText = Chart.DrawText("MasterNameChartText", masterName, index + 5, masterBars.ClosePrices[masterBarsIndexMain], "Red");
                slaveNameChartText = Chart.DrawText("SlaveNameChartText", slaveName, index + 5, slaveBars.ClosePrices[slaveBarsIndexMain] * k, "Red");
                differenceChartText = Chart.DrawText("DifferenceChartText", string.Format("Diff: {0}%", Math.Round(PercentDiffrence, 3)), index + 20, masterBars.ClosePrices[masterBarsIndexMain] + (slaveBars.ClosePrices[slaveBarsIndexMain] * k - masterBars.ClosePrices[masterBarsIndexMain]) / 2, "Red");
            }
        }
    }
}