Are all knobs not working? Does the encoder work? How about the footswitches? It could be a loose ribbon cable in the box.
It’s also worth trying to use a USB cable to connect to a PC/Mac and try if parameters change when you change knobs in the H9 Control app
Encoder switch works, foot switches work, but none of the control knobs. I’ll give H9 a try (new to me) and see if I have any luck there. Thanks.