pioneer ddj-flx4 not working on RekordBox

when i plug my controller into my macbook pro and open rekordbox, the lights turn on, but it doesn't let me control my music on rekordbox using the controller. i have rekordbox downloaded to the newest version. i have used the cable that comes with the controller, and i have used other cables but still it will not work. 

when i got the controller i linked it up to a different macbook and it worked fine, i dont know if this is the reason that it wont work on my macbook