PX4FLOW wont work

I’m trying to set up a PX4FLOW on the Intel Aero and I can’t get this thing to work. I’ve followed countless links to get it working, and none seem to work. From the intel Aero i would get values of -1 for the distances, so i assumed it was a problem with the Aero. However, I tried with a pixhawk 2.4.8 and the problem persists. I’m not sure what else i can do with this now. Anyone got an experience using the px4flow?