The CANcard is an external PCB circuit board screwed to the bottom of the PC case and connected to the locker controller computer via an external USB cable (1).
The CANcard gets its power from the external passive 24V PoE injector (b1). The PoE injector has 2 outputs on it - only the one marked Power and Data Out (2) will supply Power to the CANcard.
short microUSB cable that runs from CANcard to USB port on controller computer is not plugged in
the PoE injector (b1) is connected to the CANcard via the DATA only port not the Power+Data Out port, or is not connected at all
the PoE injector has no power - there is a little green light on the PoE injector which should be on
CANcard inside controller has failed - need replacement CANcard and follow the swap CANcard instructions
PoE injector has failed - verify with a PoE injector from another locker bank - swap out. It is a Passive 24 Volt injector. Do NOT use a 48V injector or it will damage the CANcard.