HTTP status codes / 4xx — Client errors
Blocked due to legal demands (the Fahrenheit 451 code).
The resource is inaccessible for legal reasons: court orders, DMCA takedowns, regional regulations (GDPR geo-blocks). The response may include a Link header pointing to the blocking authority.
Nothing to fix client-side; the block is policy. A different region/jurisdiction may serve the content.
Server-side note: Nothing to fix client-side; the Link header may name the blocking authority.
The fastest way to pin down a 451 is to reproduce the exact request and inspect what actually went over the wire — status, headers, timing and body, without your app code in the way. That is what an API client is for; ReqPad does it from your phone, with every request saved to history.
400 Bad Request · 401 Unauthorized · 402 Payment Required · 403 Forbidden · 404 Not Found · 405 Method Not Allowed — or the full reference.
Build the request, send it, read status + headers + timing — on your iPhone. Free to start.