To see the reason for rejection, please go to Cockpit > scroll to Last Copied Orders -> Last Slaves Orders.
You can see the final order status under the status column.

Also, please check if both master/slaves affected are CONNECTED and a Risk Factor was defined (Click Copy Settings to check, Risk Value should be at least 0.01 as a 0 value will not copy a trade).
Please note: We have known issues with scam brokers like IDSintl and Intelligence Prime that are manipulating trades, and they cannot be copied properly.