PS4 Pro brief beep (blue light) and immediately turns off

Hello,

I’ve recently acquired a PS4 Pro that won’t turn on.
When plugged in and pressing the powerbutton, the console briefly beeps one time and a blue light comes up together with it.
But other than that it does nothing. Pressing the powerbutton again gives no reaction.

The described occurrence is only repeatable after unplugging the powercord and reinserting.

Any idea where the issue might lay?

Thank you.