How Do I Set Up a 404 Page?
404 Error is the server response code which means that a requested page has not been found. Thanks to a 404 page, website visitors understand they have reached a page that does not exist. A visitor can get there if they mistyped the page address, (for example, https://ukit-help.com/nevs) or the page was deleted.
The 404 page can be changed in the Site Pages tab under System. Together with editing the page and setting up its background, you can also customize the page design: