During periods of heavy trade volume or communication latency, hanging orders may occur, which means that a Limit Order has been placed, but it is simply taking a few moments for it to be confirmed/processed.
During periods of heavy trading volumes or communication latency, it is possible that a queue of Limit Orders will form.
That increase in incoming orders may sometimes create conditions where there is a delay in confirming/processing certain Limit Orders.
In some cases, the position may in fact have been executed and the delay is simply in the client’s side display due to heavy internet traffic.
Keep in mind that it is only necessary to enter any order once. Multiple entries for the same order may slow or lock your computer or inadvertently open unwanted positions.