If you connect the microKEY/microKEY Air to your computer via a USB hub, it may not power on due to insufficient power. In that case, you should directly connect the microKEY/microKEY Air to the USB connector on your computer without using a USB hub.
Possibly there is a problem with the USB cable currently used. Please check if you can turn it on or not with the supplied USB cable.
In case when it is used in the WIRELESS mode, the power may not be turned on when the USB cable is connected. Please remove the USB cable when it is used in the WIRELESS mode.