404 Error

404 is a number your server returns when the address requested does not exist on it. To the visitor it looks like a dead end: they clicked, and instead of the expected page an error message is standing there. The number itself is only a code — 200 means “found”, 301 “moved”, 404 “not here”.

The most common causes are everyday ones. A page was deleted or renamed without the old address being redirected. A website was rebuilt and the addresses changed. Someone mistyped a link. Or an old reference from another website still points to an address that has not existed since the last rebuild.

Why this is more than a cosmetic flaw: every 404 is a visitor who wanted to reach you and did not. If the click comes from a search engine or from another website, the recommendation that this reference would have carried is lost as well. And when a page disappears that used to be found well, its visibility disappears with it.

The right way to handle it depends on what happened to the content. If it still exists at a new address, a permanent redirect belongs there — then visitors and search engines land in the right place automatically. If it genuinely no longer exists, 404 is the honest answer: a redirect to the home page is not a solution, it only confuses, because the visitor ends up somewhere they are not looking for anything.

A good error page takes the harshness out of the moment. It says in normal words that this page no longer exists, and it offers a way onward: search, the most important sections, contact. What it should not do is leave the visitor alone with an error code.

How to find them — and this is the point most people underestimate: samples are not enough. We check websites by retrieving every single address from the sitemap and logging the result, instead of looking at ten pages and assuming the rest. The reason is experience: a fault almost never sits where you suspect it.

A typical case that shows why this is necessary: a redirect rule is drawn one character too widely and therefore catches every address beginning with a particular character. The pages affected are ones that appear in no sample — on the home page and in the main sections, everything looks normal. Faults like that are only found by fetching every address individually. In our last complete check that came to 275 addresses of our own website and 68 of a client site, both without a single failure.

For you this means: a single 404 is no disaster. A pattern of 404s after a rebuild costs visibility that can only be won back laboriously. Anyone rebuilding a website should secure the list of old addresses beforehand and check every single one afterwards — not just a few of them.