DDJ FLX4 issue FX

Hello, I recently acquired a DDJ FLX4 and everything works with recordbox except one point: the FX button. The key to select the selected effect does not work and I have to manually change the effect with my computer mouse. In addition, the sound level knob for the effect is not transcribed live on recordbox (when I turn it to the right and the effect is louder, the corresponding knob does not turn on the software interface and remains at zero). Thanks in advance