First, there are four trading varieties of stock index futures, namely the current month, the next month and the next two quarters. If it is April, the contract is IF 1204? IF 1205？ IF 1206？ IF 1209 contract cannot be held at maturity, and you must choose to close the position. If it is April now, then IF 1204 contract will not exist after April.

Second, the Shanghai and Shenzhen 300 Index can be traded. Your situation may be that you have chosen a contract that cannot be traded at present. Although there are contracts such as IF 1303 in the software, it can't be traded at present. You can only trade if there is a transaction in the software.