I CAN LOAD MY TRACKS TO SERATO USING MY SX3'S BUT CAN'T PLAY

So, i recently updated my mac from system 10.9 (I know it's ancient) to system 10.14 (Mojave).

However since i've made this upload Serato won't play any tracks and It doesn't matter if i load them from iTunes or from Soundcloud. 

They load onto each deck, but they won't play. The play button doesn't work, I can't use the jog wheel or use my cue points even though they're lit up.

I've tried deleting the software and re-installing which hasn't changed at all.

Please Help!