recording function greyed out

Hi, working on rekordbox with 2 cdi 350.

Wanted to record a set recently but found out the record function was greyed out.

How can i fix this?

Rekordbox: 5.6.1

on OS X 10.9.5   or Other laptop 10.13.6   Both not working.

Tried the audiosetting, installed driver (cdi 900)  nothing works.