No audio through headphones on DDJ400 windows 8.1

Hello,

I have just got DDj400, but cannot get any audio through my headphones and computer speakers at the same time. If I choose usb line as my defeault device i will hear sound only through headphones and if i choose speakers, headphones become silent, therefore I cannot mix. Interestingly, I can hear that echo(y) sound in my headphones, like they are ready to play, but no sound comes to them.

I tried everything I found on the internet, but still no results. I dont have PC MASTER OUT button on my rekordbox, therefore I assumed problem is with drivers. This picture shows that there is no button.

However, I cannot choose DDJ400 as my driver anywhere. I tried installing several others as seen in the next picture, but none of them work. I dont have WAASPI or any other drivers i have seen on the internet. I reinstalled rekordbox several times, set my defeault device to speakers, checked windows drivers for updates but still no results. How I get my headphones and computer speakers work so I can mix?

Thank you