DDJ RR BPM Sync Problem

I got a DDJ RR and I have a problem with the BPM Sync. It was initially set to beat sync, but the tracks would diverge when beat-matching. After switching to BPM Sync, it maintains the speed, but the bars or grids are not automatically superimposed. Doesn't matter what I do, I have to beatmatch the track manually first. Which somehow doesn't make sense. Can't find a solution and ask for your help. What I've done so far: - Rekordbox uninstalled, reinstalled - Rekordbox reset all tabs - DDJ RR driver uninstalled, reinstalled. Just got a DDJ 400 from my colleague, connected it and the same problem 😳 I just made a new Pioneer DJ account in the hope that the problem would go away because I got a fresh Rekordbox, but unfortunately it wasn't the case. Both controllers DDJ 400 and DDJ RR cannot do BPM Sync. The buttons only flash happily but have no function. Just got the DDJ RR yesterday. Thanks in advance. With best regards