speaker hum and high pitch wineing sound when connected to mixer

:question: Hi,
Im geting hum and high pitch wineing sound from my Yamaha HS50M pwered studio monitors only when connected to my MACKIE 1402VLZ PRO Mixer control room outputs via balanced jacks even whe the mixer is powerd on of off with everything else not connected.

I never had this problem for many years untill now.

If the cables are not connected to the mixer the the hum and wineing noise is not there.

Any advise what could be happening?