The HTTP 403 Forbidden status code indicates that the server understands the request but refuses to authorize it. This often occurs when the user does not have the necessary permissions for a resource, or the resource is forbidden for some reason. The other status codes refer to different types of errors: 400 Bad Request indicates that the server cannot or will not process the request due to something that is perceived as a client error, 404 Not Found means the requested resource could not be found on the server, and 500 Internal Server Error indicates a generic server error when no more specific message is suitable.