macbook pro: no midi out to BCF2000

I use a Behringer BCF2000 to control my Rack, and that’s fantastic. But when I try to feed midi back into the BCF, nothing happens. Not even the Midi receive lights on the unit light up.

I have a Macbook pro, so there’s just usb-c ports. And the Behringer is an old device.

So could that be the problem, and if so, does anyone know a fix?

I tried all the modes on the BCF, no change.

Thanks, Joop