In certain situations, it is possible for an order to partially execute or fill for which there is insufficient balances in the account for the order to fully execute.
When this happens, the order will fill as much as possible and then be canceled. This will result in an order status of "Canceled".
If you click on the order ID under Trade > Orders, more information will be provided. You can see the reason for a canceled order on that page. For example:
You can also see how much of the order successfully executed on the Trade > Orders page by clicking the Order ID. This should also be reflected in your balances visible under Trade > Overview.