Browser
DNS_PROBE_FINISHED_NXDOMAIN The name does not exist
What it means
The browser asked a DNS resolver for this host name and was told that the name does not exist. Nothing at the far end can answer until the name is correct and published.
Where you usually see it
Chrome and other Chromium browsers, usually on the same screen as a dinosaur or a similar illustration. The address bar often has a typo, or the domain has expired, or it was never registered.
What to try first
Check the spelling of the host name, including missing letters and the part after the last dot. If you typed it from memory, try a known link or a search for the organisation's current site. If this is a name you just registered, wait for the DNS records to appear and confirm they were actually published.
When to stop
This is not a broken cable in your house, and it is not fixed by "flushing" things at random on a machine you do not understand. If only one name fails and others work, the problem is that name, not your whole connection.