DDJ-SB2 ''connected'' ON MAC, BUT DOSEN'T WORK

I rented a pioneer ddj-sb2 for a show tonight, I have a macbook air. I downloaded the latest version of serato and when I plug in the DDJ-SB2, it says connecting this may take up to one minute. Then in says compatible device connected but the turntables arent activating and nothing works. PLEASE HELP