DDJ-RB Channel level

Hey!

today i encountered a problem. I have a home theater which i've always used as the external audio. To listen the music i have to connect the master audio into the headphones entry on the computer, so far so good. The problem is that i used to see the volume level on the DDJ-RB faders but idk what happened, it no longer show the volume level even though the sound and everything is completely perfect. Any idea what's going on?

Thanks in advanced.