404 error is a very common website error message stating that the webpage you are looking for is not found.
This often happens when a user clicks on a link that is an outdated (or “broken”) link or when a URL is mistyped in the address field of a web browser.
Some websites display custom 404 error pages, which look very similar to the same site as others. Other websites display the default error message text of the webserver, which typically starts with “Not Found.”
Regardless of its appearance, a 404 error means that the server is active and running simultaneously, while the webpage or the path or path of that webpage is not valid.
The question arises again why it is called a “404 error” and not just a “Missing Webpage Error?”
The answer is that 404 is an error code generated by the webserver when it cannot find the web page.
This error code is well understood by search engines which helps these search engine crawlers not index such bad URLs.
404 errors can be easily read through web scripts and website monitoring tools, which helps web admins find these broken links and fix them simultaneously.
There are also other common web server codes such as 200, which means a searched webpage has been found. The second one is 301, representing that a file has been moved to a new location. Like 404 errors, users cannot see these status messages directly, but search engines and website monitoring software use them.