Why did I receive a Notice of Order Cancellation message?

If you tried to submit an order cancellation request and the Order Status field is an Orange color, that indicates that a cancellation request has been accepted by the system but currently the request is not being recognized. At this point, your order is not confirmed canceled. You may still receive an execution while your cancellation request is pending…

Overview:

The pink status indicates that you have sent a request to cancel the order, but have not yet received cancel confirmation from the order destination. At this point your order is not confirmed canceled. You may still receive an execution while your cancellation request is pending…

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…

CORPACT stands for Corporate Action. Interactive Brokers may cancel a GTC order for various reasons related to corporate actions. For example, a company may have been acquired and delisted, or there could have been a change in the contract's Cusip number. Both cases would warrant an order cancellation, and you would need to create a new order for the new symbol after the Corporate Action was processed…