The 416 Range Not Satisfiable status code indicates that the server cannot fulfill the byte range specified in the request's Range header.
For more details, refer to RFC 9110 ↗.
This error can occur when every requested byte range falls outside the selected resource. It can also occur when the server does not support the requested range unit.
A 416 response to a byte-range request should include a Content-Range header. The header uses bytes */<LENGTH>, where <LENGTH> is the current resource length.
Cloudflare can return a 416 response when the origin rejects a range request. Cloudflare can also generate this response when a cached resource cannot satisfy the requested range.
Cloudflare does not cache 416 responses returned by an origin server. This applies even when the response includes explicit cache directives or a matching Cache Rule sets a Status Code TTL for 416. This behavior prevents one unsatisfiable range request from affecting later requests for the same URL.