If your router allows it you can set your gateway IP from the router (i.e. 192.168.1.1) as the second DNS address in the DHCP settings. So your routers DNS settings would then act as fail over in case your pi-hole is down. That’s at least how I have done it on my ISP router.
If your router allows it you can set your gateway IP from the router (i.e. 192.168.1.1) as the second DNS address in the DHCP settings. So your routers DNS settings would then act as fail over in case your pi-hole is down. That’s at least how I have done it on my ISP router.