HTTP 507 – Insufficient Storage
The server is unable to store the representation needed to complete the request (WebDAV).
Common use case
Seen on WebDAV servers (like file-sync backends) when a disk or quota limit is hit while trying to save an uploaded file.
Example
HTTP/1.1 507 Insufficient Storage
History
Defined for WebDAV in RFC 2518 (1999), later carried into RFC 4918 (2007).
Did you know?
Outside of WebDAV-based systems it is almost never seen - most non-WebDAV APIs use a plain 500 or 507-flavoured 4xx of their own for storage failures.