Instruments that are based on a futures contract either have an expiry date or a rollover date. You can find out which by clicking on the "Details" link on the main trading platform screen next to the instrument’s name. Whenever a futures contract reaches its expiry date, all open positions and Orders for that instrument are terminated, regardless of any associated Orders you may have set beforehand.
For more information on rollover dates, please read “Do you offer a Rollover service?”
CFDs are complex instruments and come with a high risk of losing money rapidly due to leverage. 76.4% of retail investor accounts lose money when trading CFDs with this provider. You should consider whether you understand how CFDs work and whether you can afford to take the high risk of losing your money.