DJM Audio Out Suddenly Stops - USB Issue

Having a USB issue with my DJM900nxs. It is connected to my MacBook air via USB, and using rekordbox as software. 

I will start playing a track, it will be working fine, and then after usually around 20 or so seconds the audio will cut out. The track will continue to play in rekordbox and the USB light remains green on the DJM, but there is no sound coming out of the mixer. 

I have tried switching all of my USB cords (using cdj2000s as well so have switched those around), have tried plugging my DJM straight into my computer instead of through a USB hub, and have tried older versions of rekordbox. Drivers and firmware are all up to date. No luck.  

DJM works just fine when I play without USB and rekordbox. Any thoughts on why this could be happening?