Try resetting the Control Box by Pressing and Holding both the Up and Down buttons for 20 seconds then trying to power the lift down.
If that still does not work then the other option would be to try swapping the IEC connection the cable is drawing power from. E.g. swap the ports on the Central IEC Block with one you know is working, like the one for the projector or PC power.
If neither of these options work, contact LinkAT firstname.lastname@example.org