signal from channel 1 phono not routed to master output DJM-s9

Hi guys,

I have two technics turntables with DJM-S9 mixer. Today I suddenly noticed that signal from channel 1 phono does not route to master.
I can see signal on channel one bar, I can also hear it via headphones when connected to headphones plug on mixer but the signal doesn't appear to be sent to master output.
I connected other turntables to same channel and I have same problem, which proves there is no issue with turntable itself.
I checked input/output settings of the mixer via laptop and it appears fine.

Does anyone have any idea what could be wrong here?

Much appreciate any help.