it's a saftey feature...grabbed this from the user guide.
In normal operation when an external fault such as a short circuit on the loudspeaker leads is detected, the
amplifier will go into standby and the speaker output and AC power relays will disconnect and the MODE
indicator light will glow GREEN. Unless the fault is rectified the amplifier can not be brought out of standby.
If the amplifier output current exceeds its safe operating range (very low loudspeaker impedance and high
volume level) the Kandy integrated will revert to Standby. If subsequently the volume is lowered or the
loudspeakers changed, the amplifier can be brought out of standby to resume normal operation.