HTTP status code 404 means that the requested web page or resource was not found.
A web server or intermediary sends a 404 response when it cannot locate a resource at the requested URL. This commonly happens after a page is deleted, a link is mistyped, or a site changes its address structure without adding a redirect.
The number belongs to HTTP’s three-digit status-code system. Codes beginning with 4 indicate client-side errors, meaning the request cannot be fulfilled as made. A 404 does not necessarily prove that a server is offline.
The famous “404 Not Found” message is often customized with artwork or navigation links. It should not be confused with HTTP 500, which indicates an internal server error, or HTTP 301, which signals a permanent redirect.