404 error
A 404 Not Found means the server looked for the requested page and could not find it, usually because it was deleted, moved, or the URL is wrong. A few 404s are normal; valuable pages returning 404 by accident lose their rankings.
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Related terms
HTTP status code
A three-digit code a server returns to summarize how a request went.
Soft 404
A missing page that returns 200 OK instead of a real 404 status.
Broken link
A link that points to a URL that can no longer be reached.
410 Gone
A status code meaning a page was removed on purpose and will not return.