CDJ 2000 Nexus not connecting to Traktor 3

Hi all.

Okay, I am struggling a bit with something.

I have recently upgraded to Traktor Pro 3. Also, my wife donated an old Macbook Pro of hers to me for using with music stuff. 😊
I am trying to run through a pair of CDJ 2000 Nexus (1’s) and a DJM 900 Nexus (1).

I can open and play directly in the 900 and Traktor, so I am guessing the laptop, software and mixer are all running okay. I am using a powered hub for connectivity of the CDJ’s and the mixer directly into the laptop.

But for some reason, I cannot get the CDJ’s to connect when I hit the link button.

Everything was working fine on my old Macbook Air, old CDJ 900’s and Traktor 2.

Any help much appreciated.

Neil.