What type of error occurs when a link or hyperlink no longer works?

A 404 error occurs when a link or hyperlink no longer works because the requested resource could not be found on the server. This typically happens when the URL is incorrect, the page has been deleted, or the server does not recognize the request for that specific resource.

When a user tries to access a page that resulted in a 404 error, the server responds with a message indicating that the page is not found, which is why it's commonly encountered when clicking on outdated or broken links. This type of error is essential for web developers to address, as it impacts user experience by leading to frustration and potentially lost traffic.

In contrast, a 403 error indicates that access to the resource is forbidden, a 500 error signals a server issue, and a 301 error is used for redirecting a user from one URL to another; none of these are directly related to the unavailability of the requested resource due to it being missing or moved, as in the case of a 404 error.