Inductive Sensor works Until I hook it to control board

Hi, I put together a Hictop Prusa I3 and wanted to add a second extruder and autoleveling so I bought an OSOYOO MKS Base V1.4 3D Printer Controller remix Board ( Combination of Arduino MEGA2560 + RAMPS1.4 + 5PCS A4982 drivers) and hooked it up and adruino'd it with marlin RC6.
I hooked up the Inductive sensor to 12V and added a voltage divider on the output as per Tom Sandlanderer's Youtube video on doing that.
https://www.youtube.com/watch?v=EcGF...ature=youtu.be

The probe I got is a LJ18A3-8-Z/BX 8mm Approach Sensor Inductive Proximity NPN NO Switch DC 6-36V.

I connect the 12 V to the probe and using my meter I read the output at the divided junction and it read 4.56 volts, I put in on my bed and it goes to 0 volts..So I know its working.
When I connect it to the board its output is still 4.56 volts ..when I put it on the bed...it only drop's to 3.3 volts so it doesn't register a trigger.
I've removed all Z pullup resistors and no difference.
I'm lost as to what to do next.
Any help would be appreciated.
Thanks
Ray