Reply to problem with xone DX

Hi,
I successfully installed & mapped xone DX with Traktor Pro, used correctly driver & maps...and everything work correctly few months, but before few days when I mixed with xone, one chanel (one speaker), stopped to work (only one master out work) sometimes it's happening on few seconds, sometimes more longer...I tried also with compatable software (itch) and same happening...
I tried to reinstall driver, and that is again happening...
I tried to conect with XLR master out, and same happening...
also, I changed cable, DJ softwer...

can somebody help me?
tnx!