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