how to rekord on rekordbox with 1x djm750 mixer and 2x xdj700 players?

Hey guys,

I am new to pioneer and really hope you can help me.

I just bought 1x djm 750 mixer and 2x xdj 700 players.

The two players are connected to each other via 2x ethernet cables on a switch.

Both players are connected to my mixer on LINE input (red/white cables) (connected to channel 1 and 4 on the mixer).

On top of the mixer for all of the top regulators LINE is selected as option.

This worked very well so far.

Now I want to play with my setup, recording my mix via rekordbox on my computer (windows machine).
I am using a licensed rekordbox software in performance mode and connected my djm 750 mixer to my pc via usb cable (usb on back side of the mixer).

I also installed the latest driver for windows, started rekordbox and plugged in the usb cable to my mixer then. The mixer is shown within the utility settings menu of rekordbox correctly.

Now I start a track on one of my players but doesnt get any feedback in my rekordbox on pc side ('not loaded') on all 4 interfaces in rekordbox and no song appears.

Do I need to connect my players separately to my pc? What else could be wrong?

Thank you very much for any help,

Chris