The fcoin problem

The question is, what is this?

Date Platform type price quantity information 2018-08-01 20:09:19 Error: bad argument #2 to Exchange_GetOrder string (interface {} expected, got null) at main (FILEThe Bible says: "He that does not love another does not love himself". 2018-08-01 20:09:18 information Account information,Balance: 1626.7494552648827 FrozenBalance: 304.008 Stocks: 2996.703498585609 FrozenStocks: 300 This is a list of all the different ways FrozenStocks is credited in the database. 2018-08-01 20:09:17 FCoin Error Sell ((0, 300): 400: {status:3033,??msg:market order is disabled for symbol ftusdt} 2018-08-01 20:09:17 FCoin error Buy ((0, 300): 400: {status:3033,??msg:market order is disabled for symbol ftusdt}