rekordbox keeps crashing

Hey. I have problems with rekordbox, i can open it and drag song to the play section and they will play but when i plug in my dj controller (ddj-flx4) it crashes and there will be this ''unexpected application error'' notification. I have tried to uninstall and re-install rekordbox but it won't help. I was trying earlier to install stems to the rekordbox but it didn't work so i just deleted the stem files, also accidentally deleted the folder where my rekordbox was but then just returned it from the trashbin.