First, make sure the physical power switch located on the left side of the Power Box is turned on. Press it firmly once until you feel a slight click and the switch sinks in.
After turning on the physical switch, short-press the power button on the top of the Power Box to power on the device. If there is still no response, try pressing the top power button slightly more firmly with a short press only. Do not continuously hold the button down.
If the issue still persists, please provide:
A short video showing your operation steps and the Power Box response status.