DDJ-FLX6 works on first use of Rekordbox, not when I restart

On first install of Rekordbox (probably same with Serato), the DDJ-FLX6 is able to control Rekordbox and also the sound, however, once I restart Rekordbox, the controller is still able to control Rekordbox, but now there's no more sound! Please see video, it has happened on 3 computers!

When I try to use DDJ-1000 ASIO as the audio option in Rekordbox I get an "Error while opening 'DDJ-1000 ASIO". Not sure if I'm supposed to use a different audio option since I have the FLX6. The DDJ-FLX6 WASAPI or my Realtek Speaker options don't work either.

If I unplug the controller and use the computer to run Rekordbox, I get the sound. If I plug the controller in with the USB, it stops working!

I've made sure the default speakers are the computer and not "Line".

They are all Intel computers, I don't know if that makes a difference

https://www.reddit.com/r/PioneerDJ/comments/y3bpip/ddjflx6_works_on_first_use_of_rekordbox_not_when/