The message refers to who cancelled the order. As an example, Cancelled by System is a message you will see when one OCA leg of an order is canceled by the User then the IBKR system will cancel the other leg of the OCA Group. The message for the first leg will be displayed as User Cancelled as the user acted to cancel the order. The other OCA leg message will show Cancelled by System as the IBKR system was active in cancelling that order. An Invalid Order means the order was either created incorrectly and when submitted the IBKR system would not accept the order. Or the Invalid Order was created in a manner the exchange would not accept or a change occurred like the contract expired so the exchange could no longer hold the order.
What does "Cancelled by system invalid order" mean?
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