no sound through studio monitors!!!

[Southernbudz]

Okay so today i decided to record some vocals.
after i was done, i went back to my studio (microphones in another room)
to listen to my vocals through my studio monitors.

(i have two krk rokit powered 5 monitors)

when i push out the mon mute on my mbox 2 mini
i cant seem to hear anything from my monitors, not a sound!

i used to be able to push out the mon mute and hear it
through my right krk monitor (that was when i had one monitor)

please help if you know how to fix this problem, please and thank you!