When use the Novastar system,, showing the sending card is existent,but can't detect the receiving card , how to solve?

Check whether the sending card has connected to the cable in the control box and the cabinet has connected to electricity .if do as above , restart the system and re detect the receiving card after changed the LAN cable ,if still can’t detect ,replace the control cabinet and try again.after that if can detect,that means electric box abnormal .