Have you followed the instructions in the DVS setup guide?
DJM 250mk2 paired with Pioneer PLX 1000 not communicating between one another?
I just downloaded rekordbox and hooked it all up. RCA to Phono on turntables to RCA in the back up my mixer. All is set up in DJM Setting utility and in rekordbox via audio and it will not register when I do anything on the turntables.