Hi indrek,
Check to make sure that the A on the left of the crossfader is yellow (click it if it is greyed out and it will turn on)
Screen Shot 2018-06-17 at 10.09.35 AM.png
I was able to replicate the same behaviour you described by turning off the crossfader for deck A, and this could easily be accidentally clicked.
I hope it is something this simple!
Regards,
Adam @Mixvibes
You do not have the required permissions to view the files attached to this post.