What visitors see when something is not found.
WHY BOTHER
The default server error page is bare, unbranded, and looks like the site is broken rather than the page being missing.
A custom page keeps visitors on the site and gives them somewhere to go.
SETTING THEM UP
cPanel > Error Pages lets you create pages for common codes through the interface.
Or add directives to .htaccess pointing each error code at a page you have created.
WHICH TO CUSTOMISE
404, by far the most important 403, for permission errors 500, for server errors
A GOOD 404 PAGE
Explains plainly that the page was not found Offers a search box Links to the main sections Gives contact details Matches the site design
A GOOD 500 PAGE
Must be static, with no application code, since the application is what failed. A 500 page that itself requires PHP shows nothing.
TRACKING THEM
Monitor 404s in analytics or the access log. A pattern reveals broken links, changed URLs, or a scanner probing for vulnerabilities.
