ftp · ftp/421
421
Service Not Available
The service is not available and the control connection is being closed. Typically sent when the server is shutting down or overloaded.
Also defined in
- http Misdirected Request The request was directed at a server that is not able to produce a response for the requested URI.
- sip Extension Required The server requires a specific extension that is not listed in a Supported header field in the request. The response includes a Require header indicating the needed extension.
- smtp Service not available The server is temporarily unavailable and is closing the connection. The client should retry later.