problem the track sounds on the 2 channels in flx4

I bought a flx4 and when I connected it the master sounded very low, after playing settings I was able to send the sound externally to a Focusrite only, but the option to regulate the master disappeared, and now, in the controller, it marks the track playing on both channels at the same time. but in rekordbox it shows me only one playing. I also accepted a firmware update in rekordbox, from a window that appeared asking to update. How can I fix it, since it saturates the master output.