Description for "Page not Found "
One or more internal links point to pages that return the HTTP-statuscode 404 (Page Not Found). These links and linktargets should be checked and either be corrected or deleted. A link to a page that no longer exists is something that is neither helpful for a user, who is shown an error page, nor good for searchengines. A large number of defective or dead links can be a negativ ranking-signal for Google.