Temporary failure in name resolution for localhost querries

I did change something before this started I unchecked these two boxes

Advanced DNS settings
X Never forward non-FQDNs
X Never forward reverse lookups for private IP ranges

Note that enabling these two options may increase your privacy slightly, but may also prevent you from being able to access local hostnames if the Pi-hole is not used as DHCP server

Re enabling those two option fixed it.

Does that mean there is another DHCP server besides my router?

The Pi-Hole DHCP server is not enabled.