On rare occasions, an order submitted to a trading venue may be cancelled and a confirmation of the order cancellation will appear with the below cancel reasons;

Order Cancelled ReasonDescription
CANCEL_REQUESTThe order was cancelled as a result of
a user request to cancel it
BY_EXCHANGEThe order cancellation was initiated by
the exchange (trading venue) itself
ORDER_MODIFIEDThe order cancellation was initiated
automatically after a modification
BY_ADMINThe order cancellation was initiated by
an admin user