The reason for DNS_PROBE_FINISHED_NXDOMAIN is typically due to a misconfiguration or problem with your DNS. DNS is short for Domain Name System, which helps direct traffic on the internet by connecting domain names with actual web servers. Essentially, it takes a human-friendly request – a domain name like kinsta.com – and translates it into a computer-friendly server IP address – like 216.3.128.12.
When a user enters a URL in their web browser, DNS gets to work to connect that URL to the IP address of the actual server. This is called DNS name resolution and involves a DNS recursor querying various nameservers to figure out the actual IP address of a server. If DNS fails to resolve the domain name or address then you might receive the DNS_PROBE_FINISHED_NXDOMAIN error. The NXDOMAIN part stand stands for Non-Existent Domain. Read more about DNS and how it works.