Rekordbox mobile

At first, I registered for Rekordbox using a laptop...it can sync with Rekordbox mobile...as soon as I move to another computer, now it can't...and my Rekordbox display on another computer also doesn't have a volume button on the top right .... and the audio output from flx4 is also unreadable...can only output speakers from the computer...how are the settings...thank you...and the account on my laptop has been deactivated, now I only log in to 1 computer