It’s possible you might have all your decks switched to channel output mode. Look at the front of the unit you will see 4 switches for the 4 channels. Make sure each switch is on Deck mode.
Be careful, this unit will keep you up all night long enjoying all that is possible with it. I’ve had the SC5000/5000M and this all in one unit is so much more convenient and fun than the big brother seperate units.
They just need the Denon Prime 4 motorized version and my DJ life will be complete.