Board Thread:Support Requests - Getting Technical/@comment-34753919-20180815231125/@comment-9605025-20180815235307

First, you need to be an admin on the wiki you want to change it for. On that wiki, go the "MediaWiki:Custom404page-noarticletext-alternative-found". Depending on whether or not it has been changed on the past, you will either create or edit that page with the content you want to display.