Please help me I’m new

Cannot play sound from built in speakers and headphones at same time. I just got a DDJ FLX4 yesterday and set it all up using Rekordbox and it worked fine. I had Music coming through my laptop and my headphones. Now it only works from the headphones but will not play through my laptop. What can I do To fix this? I’ve seen a lot of post saying it could be the usbc cord that was sent with the flx4?