Recordbox recording problems with ddj-rx, everything is up to date!

I cant record in performance mode, when i have my ddj rx connected my computer, it records but the wave form comes flat and no sound comes out of the "recording session" its just a white flat line instead of wave forms.. But when i only record in performance mode only whit computer no controller connected it records perfectly, what is the problem and what do i need to do to fix the problem?
Im running macbook pro MAC OS MOJAVR 10.14.5