Firefox added a new "feature" that is on by default in the latest version of Firefox browser.
The error is caused by DNS over HTTPS being enabled with the
latest version of Firefox. Be prepared for a lot more of these.
Updating the setting is simple on Firefox
- Click the menu on the right hand side and select Options on windows (or Preferences on Mac Os)
- Scroll to the bottom of the options screen to find Network Settings and click on the settings button
- A checkbox for DNS over HTTPS will be checked by default
- Uncheck that box and close the browser.
Restarting the browser now should fix the access issues.