In computer network communications, the 404 error message (HTTP 404) is a hypertext transfer protocol (HTTP) standard response code, to indicate that the browser was able to communicate with a given server, but the server could not find what was requested.
The error may also be used when a server does not wish to disclose whether it has the requested information. A 404 status code does not indicate whether this lack of representation is temporary or permanent; the 410 (Gone) status code is preferred over 404 if the origin server knows, presumably through some configurable means, that the condition is likely to be permanent. HTTP substatus codes are listed in the footnotes[1].
The typical cause for an error 404 message is when website content has been removed or moved to another URL. Other reasons include: the URL or its content (such as files or images) was either deleted or moved (without adjusting any internal links accordingly);
the URL was written incorrectly (during the creation process or a redesign), linked incorrectly, or typed into the browser incorrectly; the server responsible for the website is not running or the connection is broken; the requested domain name can’t be converted to an IP by the domain name system (DNS); or the entered domain name doesn’t exist (anymore).
404 errors should not be confused with DNS errors, which appear when the given URL refers to a server name that does not exist. A 404 error indicates that the server itself was found, but that the server was not able to retrieve the requested page.
How to possibly fix 404 errors
- Reload the page: It might be that the error 404 has appeared for the simple reason that the page did not load properly. This can be checked quite easily by clicking on the ‘Refresh’ button in your browser or also by pressing the F5 button.
- Check the URL: Regardless of whether you have entered the URL address manually or been directed via a link, could be that a mistake has been made.
- Go back through the directory levels: For example, if a URL of the following structure example.com/Directory1/Directory2/Directory3 causes a 404 error page, then you can always go back to the previous directory level (in this example: example.com/Directory1/Directory2) in order to check whether the desired page is linked there.
- Use the website’s search function: Many websites offer a search function as part of their homepage.
- Use a search engine: You also have the possibility of using the website of your choice to find a website. As long as the desired site exists, you should be able to find it.
- Delete the browser cache and cookies: Ifyou can access the website from another device, and the HTTP 404 error only seems to appear on a certain computer, then the problem could lie with your browser.
- Contact the website: If none of the abovementioned tips have been successful then the only remaining option may be to get in touch with the person/people responsible for the website. Contact information can usually be found in the website’s masthead or else on a specific ‘Contact Us’ page.
There are tools available to check for dead links (404 errors) on your own websites like Google Search Console, Dead Link Checker, and W3C Link Checker. The HTTP 404 page is just a simple standard error message, but most of them can be personalized using special CMS extensions.
Footnotes
- HTTP substaus Codes
- 404.0 – Not found.
- 404.1 – Site Not Found.
- 404.2 – ISAPI or CGI restriction.
- 404.3 – MIME type restriction.
- 404.4 – No handler configured.
- 404.5 – Denied by request filtering configuration.
- 404.6 – Verb denied.
- 404.7 – File extension denied.
- 404.8 – Hidden namespace.
- 404.9 – File attribute hidden.
- 404.10 – Request header too long.
- 404.11 – Request contains double escape sequence.
- 404.12 – Request contains high-bit characters.
- 404.13 – Content length too large.
- 404.14 – Request URL too long.
- 404.15 – Query string too long.
- 404.16 – DAV request sent to the static file handler.
- 404.17 – Dynamic content mapped to the static file handler via a wildcard MIME mapping.
- 404.18 – Query string sequence denied.
- 404.19 – Denied by filtering rule.
- 404.20 – Too Many URL Segments.
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