It is only possible to close a position (trade) during the trading hours of the financial instrument. In addition, occasionally, financial instruments may be temporarily unavailable for trading when market events restrict price feeds, i.e. linked to extreme volatility, illiquidity, underlying market suspensions, etc.
CFDs are complex instruments and come with a high risk of losing money rapidly due to leverage. 72.7% 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.