GetOHLC and GetLTP returning errors

          /// <summary>
            /// Retrieve LTP and OHLC of upto 200 instruments
            /// </summary>
            /// <param name="Exchange">Name of the exchange</param>
            /// <param name="TradingSymbol">Tradingsymbol of the instrument</param>
            /// <returns>Json response in the form of nested string dictionary.</returns>
            try
            {
                Dictionary<string, OHLC> ohlcs = kite.GetOHLC(new string[] { "MCX:ALUMINI17NOVFUT","MCX:ALUMINIUM17NOVFUT","MCX:COPPER17NOVFUT","MCX:COPPERM17NOVFUT","MCX:COTTONREF17NOVFUT","MCX:CPO17NOVFUT","MCX:GOLDGUINEA17NOVFUT","MCX:GOLDPETAL17NOVFUT","MCX:LEAD17NOVFUT","MCX:LEADMINI17NOVFUT","MCX:MENTHAOIL17NOVFUT","MCX:NICKEL17NOVFUT","MCX:NICKELM17NOVFUT","MCX:RBDPMOLEIN17NOVFUT","MCX:SILVER100017NOVFUT","MCX:SILVERM17NOVFUT","MCX:SILVERMIC17NOVFUT","MCX:ZINC17NOVFUT","MCX:ZINCMINI17NOVFUT" });
                Console.WriteLine(JsonSerialize(ohlcs));
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.Message);
            }



            //// Get LTP of upto 200 scrips
            /// <summary>
            /// Retrieve LTP of upto 200 instruments
            /// </summary>
            /// <param name="Exchange">Name of the exchange</param>
            /// <param name="TradingSymbol">Tradingsymbol of the instrument</param>
            /// <returns>Json response in the form of nested string dictionary.</returns>
            try
            {
                Dictionary<string, LTP> ltps = kite.GetLTP(new string[] { "MCX:ALUMINI17NOVFUT", "MCX:ALUMINIUM17NOVFUT", "MCX:COPPER17NOVFUT", "MCX:COPPERM17NOVFUT", "MCX:COTTONREF17NOVFUT", "MCX:CPO17NOVFUT", "MCX:GOLDGUINEA17NOVFUT", "MCX:GOLDPETAL17NOVFUT", "MCX:LEAD17NOVFUT", "MCX:LEADMINI17NOVFUT", "MCX:MENTHAOIL17NOVFUT", "MCX:NICKEL17NOVFUT", "MCX:NICKELM17NOVFUT", "MCX:RBDPMOLEIN17NOVFUT", "MCX:SILVER100017NOVFUT", "MCX:SILVERM17NOVFUT", "MCX:SILVERMIC17NOVFUT", "MCX:ZINC17NOVFUT", "MCX:ZINCMINI17NOVFUT" });
                Console.WriteLine(JsonSerialize(ltps));
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.Message);
            }