All futures contracts expire. Each commodity has a specific, predetermined time that its contracts will expire. This is also true on papertrademe.com. 14 days before a futures contract that you are in is set to expire, the status will change to “Expiring”. And then on the day of expiration it will show “Expired”.
Unless you are planning on taking delivery of the commodity (very few want to do this), you should get out of the trade 8-14 days before the expiration date. (Expiration dates for different commodities vary.) If you want to continue trading that specific commodity, however, then you should “rollover” the contract to the next available trading month. Rolling over a contract is simply exiting the expiring month’s contract and entering a new contract in a further out month.