How to get rid of IPPON 2200 Smart Power noise effect when it is turned off?

Question

Uninterruptable power source

IPPON 2200 Smart Power recently bought an uninterruptible power supply and was happy with everything, BUT, even when the computer and all the electronics that work through it are completely turned off at night, it turns on at night, and I hear the sound of fans that start working. It can turn on and off many times during the night, and I can hear the sound of its work continuously, while the on / off button is completely turned off! Is there any way to get rid of this effect?