Hue cabinet light strip not reachable

I have successfully installed two light strips and everything works fine. A third strip is not recognized in the Hue app, even if I enter the serial number. The lights will light, but are not controlable (no on/off, color change, or dimming). The only difference is that I used two- conductor low voltage wires installed in the studs behind the cabinets. I cut the output wires from the power supply and connected them to the wires embedded in the walls. I then spliced in the wifi receiver to the other end of the two-conductor wires in the walls. I tried reversing polarity of the wires. One way turns the lights on and the other way lights are off. Neither way is recognizable. The wifi is about the same distance to the hub as the other two working lights, so signal should be OK. Any suggestions?