Question about DDJ400, Rekordbox and Windows...

I recently bought a pair of monitors and a Focusrite Scarlett 2i2 audio interface, so far they work great. Yesterday I connected my DDJ400 to the audio interface with an RCA to 1/4 Jack cable. I spent a moment trying to get the interface to recognize the DDJ400 but finally succeeded, but when I opened Rekordbox I started having more problems.

In the audio preferences I selected the DDJ400 as the output for the sound, but I play anything and there is no sound. I did the same procedure on my Macbook and everything works perfectly. The only difference between the Macbook and Windows is that on the Mac the "Output audio from the computer's built-in speakers and your DJ equipment" option is enabled.

I tried again activating that same option in Windows (as in the screenshot I uploaded), it works for a few seconds (the sound is heard in the monitors and also in the headphones) but the music starts to crash, I hear strange sounds and the audio stops at times

Does anyone know what I could do? Is there something additional I have to configure in Windows or Rekordbox?