pi-hole on RPi freezes

I installed Pi-Hole on on of my old RPI Model B from 2012
After install Pi-Hole works fine
But then after a while the RPI freezes completely
SSH connection disconnect too and i have to power off the device

I know its an old device but would be perfect for this kind of using
a second test installation on my Odroid XU4 runs perfect since 3 days

It is a problem of the old Raspberry ?

99.9% sure its a unstable/faulty PSU. But it might be worth checking htop (swap/RAM usage) to see if you need to increase the swapfile size. This can be done in dietpi-config advanced.

I’d recommend trying another PSU and different SD card if you have one (just to be sure).