Did not proceed BadVolume

Hello,

I am getting this issue in my cBot. Please can you assist? 

using cAlgo.API;
using cAlgo.API.Indicators;

namespace cAlgo.Robots
{
    [Robot(TimeZone = TimeZones.UTC, AccessRights = AccessRights.FullAccess)]
    public class EmaCrossoverRobot : Robot
    {
        [Parameter("MA1 Period", DefaultValue = 9)]
        public int MA1Period { get; set; }

        [Parameter("MA2 Period", DefaultValue = 13)]
        public int MA2Period { get; set; }

        [Parameter("MA3 Period", DefaultValue = 21)]
        public int MA3Period { get; set; }

        [Parameter("MA4 Period", DefaultValue = 55)]
        public int MA4Period { get; set; }

        [Parameter("Leverage (as a decimal)", DefaultValue = 0.10)]
        public double Leverage { get; set; }

        public bool TradeInProgress = false;
        private ExponentialMovingAverage ma1;
        private ExponentialMovingAverage ma2;
        private ExponentialMovingAverage ma3;
        private ExponentialMovingAverage ma4;

        protected override void OnStart()
        {
            Print("Started Bot");
            ma1 = Indicators.ExponentialMovingAverage(MarketSeries.Close, MA1Period);
            ma2 = Indicators.ExponentialMovingAverage(MarketSeries.Close, MA2Period);
            ma3 = Indicators.ExponentialMovingAverage(MarketSeries.Close, MA3Period);
            ma4 = Indicators.ExponentialMovingAverage(MarketSeries.Close, MA4Period);
        }

        protected override void OnTick()
        {
            Print("Tick called");
            Buy();
            Sell();
        }

        protected void Buy()
        {
            double leverage = Leverage;

            double totalEquity = Account.Equity;
            double volumeInUnits = (totalEquity * leverage) / MarketSeries.Close.LastValue;

            Print("Buy test check = " + (ma4.Result.HasCrossedBelow(ma1.Result, 1) &&
                ma4.Result.HasCrossedBelow(ma3.Result, 1) &&
                ma4.Result.HasCrossedBelow(ma2.Result, 1)));
            Print("Trade in progress = " + TradeInProgress);
            Print("MA1 = " + ma1.Result.LastValue + " Crossed " + ma4.Result.HasCrossedBelow(ma1.Result, 1));
            Print("MA2 = " + ma2.Result.LastValue + " Crossed " + ma4.Result.HasCrossedBelow(ma2.Result, 1));
            Print("MA3 = " + ma3.Result.LastValue + " Crossed " + ma4.Result.HasCrossedBelow(ma3.Result, 1));
            Print("MA4 = " + ma4.Result.LastValue);

            if (ma4.Result.HasCrossedBelow(ma1.Result, 1) &&
                ma4.Result.HasCrossedBelow(ma3.Result, 1) &&
                ma4.Result.HasCrossedBelow(ma2.Result, 1) &&
                !TradeInProgress)
            {
                Print("Execute Buy for Symbol = " + Symbol.Code + " Volume = " + volumeInUnits + " EMA Cross UP");
                var result = ExecuteMarketOrder(TradeType.Buy, Symbol, 500, "Buy Order", null, null, null, "EMA Cross UP");

                if (result.IsSuccessful)
                {
                    var position = result.Position;
                    Print("Position entry price is {0}", position.EntryPrice);
                    TradeInProgress = true;
                }
                else
                {
                    Print("Execute Buy for Symbol = " + Symbol.Code + " Volume = " + volumeInUnits + " Did not proceed " + result.Error.Value);
                    TradeInProgress = false;
                }
            }
        }

        protected void Sell()
        {
            double leverage = Leverage;

            double totalEquity = Account.Equity;
            double volumeInUnits = (totalEquity * leverage) / MarketSeries.Close.LastValue;

            Print("Sell test check = " + volumeInUnits);
            Print("Trade in progress = " + TradeInProgress);
            Print("MA1 = " + ma1.Result.LastValue);
            Print("MA2 = " + ma2.Result.LastValue);
            Print("MA3 = " + ma3.Result.LastValue);
            Print("MA4 = " + ma4.Result.LastValue);

            if (ma4.Result.HasCrossedAbove(ma1.Result, 1) &&
                ma4.Result.HasCrossedAbove(ma3.Result, 1) &&
                ma4.Result.HasCrossedAbove(ma2.Result, 1))
            {
                // Close all open positions for the current symbol
                foreach (var position in Positions)
                {
                    if (position.SymbolCode == Symbol.Code)
                        ClosePosition(position);
                }
                TradeInProgress = false;
            }
        }
    }
}