https://www.helpnetsecurity.com/2015/12/22/http-error-code-451-will-signal-online-censorship/
HTTP error code 451 will signal online censorship - Help Net Security
Feb 6, 2019 - A new, official HTTP error code has been assigned to denote instances where governments restrict access to specific websites: 451. The number is a
http error codeonline censorshiphelp net451
https://www.inmotionhosting.com/support/website/error-numbers/406-not-acceptable/
406 Not Acceptable: HTTP Error Code and How to Fix It
Sep 15, 2023 - This article explains what HTTP error code 406 is, what causes it, and how to correct it if it happens on your site.
406 not acceptablehttp error codehow to fix