Historical trade - Crashed in OnTick with NullReferenceException:

Hi,

My code crash when try to pull historical trade data

This is the issue - HistoricalTrade ht = History.FindLast("RobotID1"); 

When I tried to use the variable     ht.       for anything it will crash.

please help.

Thanks.

This is my code.

using System;
using System.Linq;
using cAlgo.API;
using cAlgo.API.Indicators;
using cAlgo.API.Internals;
using cAlgo.Indicators;

namespace cAlgo.Robots
{
    //Set time zone to Eastern Standard Time EP9-Best time to trade
    [Robot(TimeZone = TimeZones.EasternStandardTime, AccessRights = AccessRights.None)]
    public class EP12NNFXBot : Robot
    {
        //Create Parameters EP10-Functions and Parameters
        [Parameter("Risk %", DefaultValue = 0.02)]
        public double RiskPct { get; set; }
        
           [Parameter("Stop Loss", Group = "Protection", DefaultValue = 40)]
        public int StopLoss { get; set; }

        [Parameter("Take Profit", Group = "Protection", DefaultValue = 40)]
        public int TakeProfit { get; set; }
        
        [Parameter("Tradeamount: ", Group = "Protection", DefaultValue = 40)]
        public int TradeAmount { get; set; }


         [Parameter("Robot Label", DefaultValue = "buy eurusd")]
        public string RobotID1 { get; set; }

        //Create indicator variables EP5-ATR
                public TDFInnfxabbu tdfi;
                public double GrossProfit { get; }
                public double VolumeInUnits { get; }
                public double NetProfit { get; }

        private Random random = new Random();
        

        protected override void OnStart()
        {
        
       // Open(TradeType.Buy, "RobotID1",1000);
       Open(GetRandomTradeType(), "RobotID1",1000);
        HistoricalTrade ht = History.FindLast("RobotID1");

        }

        protected override void OnTick()
        {
            // Put your core logic here EP7-MACD and EP8-Custom Indicators
            //var TradeAmounts = TradeAmount;
            HistoricalTrade ht = History.FindLast("RobotID1");


            //Check Entry Signal
            if  (ht.NetProfit > 0 & Account.Equity < 400)

            {
                //Open(GetRandomTradeType(), "RobotID1",1000);
                Open(GetRandomTradeType(), "RobotID1",1000);
                
                
            }
            else if ( Account.Equity < 400) //ht.NetProfit < 0 &
            {
                Open(ht.TradeType, "RobotID1",ht.VolumeInUnits);
                //Open(GetRandomTradeType(), "RobotID1",1000);
            }

            //Check Exit Indicator
            //if (Account.Balance < MaxEquity & (History.Last().TradeType == TradeType.Sell))
            {
                //Open(TradeType.Sell, "RobotID1",1000);
                
            }
            //else if (Account.Balance > MaxEquity & (History.Last().TradeType == TradeType.Sell))
            {
               //Open(TradeType.Sell, "RobotID1", 1000);
               //();
            }

        }
        //Function for opening a new trade - EP10-Functions and Parameters
        private void Open(TradeType tradeType, string Label, double tradeamount)
        {

            var position = Positions.Find(Label, SymbolName);
            //var tradeamount = 1000;
           
           
            if (position == null & Server.Time.Hour == 16 & Server.Time.Minute == 29)
                ExecuteMarketOrder(tradeType, SymbolName, tradeamount, Label, StopLoss, TakeProfit);
        }

        //Function for closing trades - EP10-Functions and Parameters
        private TradeType GetRandomTradeType()
        {
            return random.Next(2) == 0 ? TradeType.Buy : TradeType.Sell;
            }
        private void Close(TradeType tradeType, string Label)
        {
            foreach (var position in Positions.FindAll(Label, SymbolName, tradeType))
                ClosePosition(position);
                
                
        }
        
    }
}