What does HTTP status 404 mean and what is its essence?

HTTP status 404 means "Not Found" — the resource requested by the client (such as a web page or file) was not found on the server.

The essence of this code is that the server successfully processed the request but could not find the specified URI. This can happen if:

• The user entered an incorrect URL.
• The resource was deleted or moved.
• The link is outdated.

In response with a 404 code, the server usually sends an error message page informing the user that the required content is missing.