416 Range Not Satisfiable
Meaning
The client has asked for a portion of the resource (via the Range header), but the server cannot supply that portion. Often because the requested range is outside the size of the target file.
When to Use
When responding to a Range request where the range specifications cannot be met. The server should include a Content-Range header indicating the valid range if possible.
Example
If a client requests bytes 500-999 of a file that is only 300 bytes long, the server responds with 416 Range Not Satisfiable, possibly including Content-Range: */300 to indicate the size.
When Not to Use
Do not use for requests without Range headers. If the request isn't a range request, there's no range to be unsatisfiable (other errors might apply instead if something else is wrong).
Source
RFC 9110