Running a local DNS server is great - until your devices ignore it ...
DNS server isn't responding,' 'DNS lookup failed,' 'NXDOMAIN' and 'DNS resolution timeout' are just some of the possible ways your browser or internet-enabled device tells you there is a DNS failure.
You can fix a "DNS Server Not Responding" error by resetting your internet connection and computer. If the error keeps appearing, you can also flush your DNS cache ...