Why orders submitted via Ninja Trader were cancelled or rejected?

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…

The TWS Application Program Interface (API) accommodates connection to a variety of third-party vendors, including Ninja Trader, who offer complementary order entry, charting, back-testing and analytics software programs designed to expand the functionality of TWS. Please see the…

To pause an active order in Classic TWS or Mosaic, right-click a working order and select Pause Execution. When you pause a working order, a cancel request is submitted to the exchange and the order is put into an inactive state but remains available on the Orders panel (Mosaic) or Quote Monitor (Classic TWS) for you to resubmit at any time. Please note, the paused order is still included in the value of open but unexecuted orders by the IBKR Credit system because it is queued up and ready to be re-transmitted. To re-submit a Paused order, click on the Transmit button on the order row again. …

If you do not have sufficient funds to cover the Initial margin requirements for a futures contract order, the following will occur:

1. Order Rejection: Your order will be automatically rejected by our system.
2. Error Message: You will receive an error message on your trading platform…