Yes, you can.

If you start copying a strategy when the market is closed, current open orders in the strategy will not be copied to your newly created investment. Only new orders will be copied. 

If you stop copying a strategy when the market is closed, the orders within your investment will be closed as soon as the prices come in when the market reopens for the instrument traded. 

If you are choosing to stop copying when the market is open, the orders will be closed immediately. 

Note:

• If your investment includes multiple trading instruments, each order will be closed based on the individual market opening times of those instruments. As a result, when you stop copying while the market is closed, some orders may remain open until their respective markets reopen. Find out what the trading hours are for all instruments.
• An investment will automatically stop if a strategy’s equity drops to 0.