Description

A 404 Error – Page not found shows when the page requested does not exist.It is a client-side error : the server receives a request, but cannot carry it out. The reason for this is usually a faulty client request. The HTTP status code 404 means that the requested website data could not be found on the server. This could mean that the web address no longer exists or the content has been moved to a new address.

The 404 page should explain what the issue is and offer suggestions to move out from it back to browning the site. 404 pages are important for the user experience.404 pages are usually quite straightforward but some companies show a creative 404 error page. The most important is to let the user and Google know about it while helping the user to find his way fast. For example here for Zalando:

In order to avoid such pages:

You would need to render a catch-all page for pages not yet covered. For example in Node.js:

app.all("*", function(req, res) {
    res.status(404).render("error");
});

Why I am receiving a 404

Most common: The url entered or the domain name does not exist or the url was typed incorrectly

Less common but still possible: the webserver is down

Effect of 404s on SEO

There should be no broken links nor internal links pointing to a 404. These are wrong signals for Search Engines. These can be solved by running a crawl and correcting the links or if this cannot be done for external links, by setting up redirects. Also it is advisable to set up a 404 page if this has not yet been done.