If your foxflash bench box stop working, here is the possible solution.
the problem usually comes from the relay. This relay gives power.
the blue bench box, the relay is the one that sends the 12 vdc to the ECU. if there is no 12v, it is impossible to connect to the ECU.
P channel mosfet burned. Near relay.
change it: DMP3010LK3-13, MOSFET P-CH 30V 17A TO252-3
And at better install 5A fuse, to powerline after box.
If do the above but have no effect, there are other problems. Contact your dealer.