NVR turns itself off and on

Hi all, I am seeking some help please. I have a hikvision system and whenever the NVR is connected to my network the NVR continually turns off and then back on - once it reboots it turns off and then on again.
rinse repeat

I have no idea what would be causing this.
I have tried different cables, plugging the nvr into my switch, plugging it direct to the router to no avail.

Thanks