What is it connected to? An NVR? a Switch
Are there other cameras also plugged in?
How are you viewing it and knowing its off after an hour?
When they are first plugged in, to a Dahua NVR, they will be given an IP address by the NVR on a 10.1.1.X subnet, and adopt its password
When they are first plugged into an external switch, they will ALL default to 192.168.1.108.
You must login and change that to another IP before plugging in another one or there will be an IP conflict both trying to use the same IP.
It sounds like the latter, and they will battle it out being alive then dead until you change the IP's and reboot them both
yes it must be powered for the reset switch to work but it will default to the same 192,168.1.108 so that's an effort in futility