U-Mix Control Pro - NO HEADPHONE AUDIO

Hi there
I'm using Cross DJ 3.3.11.
Output sound is working for both channels. both there is no audio to the headphones, only a very very faint hiss when volume is turned on full.
Updated firmware, and tried both versions U-Mix Control Pro v4.2 and V4.3, with no success.
Is it a hardware problem??
help...
I'm using Cross DJ 3.3.11.
Output sound is working for both channels. both there is no audio to the headphones, only a very very faint hiss when volume is turned on full.
Updated firmware, and tried both versions U-Mix Control Pro v4.2 and V4.3, with no success.
Is it a hardware problem??
help...