What does 401 Unauthorized mean?

The "401 Unauthorized" status code is an HTTP response that indicates the request lacks valid authentication credentials or the provided credentials are incorrect. This error typically occurs when a user attempts to access a restricted resource or page without being logged in, or when their session has expired.

For example, if a user tries to access a private account page without being logged in, the server will respond with a 401 Unauthorized status, prompting them to enter valid login credentials. This status helps protect sensitive information by ensuring that only authorized users can access specific resources, enhancing security and privacy.