Pro DJ Link won't connect

Hi,

I want to connect my Macbooks Pro DJ Link app to my CDJs 3000 Players but it won't work.

The Rekordbox will connect via Link but the Pro DJ Link app not. I only have CDJ 3000 Player and no Mixer which has got network connection, could that be the problem? Do I need a compatible mixer, too or should it work with just the CDJ 3000 player?

Thank you very much, Markus.!