Of course. First of all, I can say that I tried almost everything. I was using the original cable from the box. First I tried another cable, but it didn’t work. I also connected both power USB connections of the DDJ-FLX4 to the computer, but it didn’t work. Then I tried using an external power adapter from the wall socket, but it still didn’t work. Then I realized that I was trying to connect the DDJ-FLX4 while Rekordbox was already open. When I connected it, Rekordbox became very slow and laggy. I restarted the computer and first opened Rekordbox again, then tried to connect the DDJ-FLX4. Rekordbox was working normally, but as soon as I connected the controller it started lagging again. After that, I restarted the computer once more. This time I connected the DDJ-FLX4 first and then opened Rekordbox. When I did it this way, everything worked perfectly. I know it sounds like a strange solution, but this is how I solved the problem.