HTTP status codes / 4xx — Client errors
The server insists on a Content-Length header.
The server refuses chunked or length-less bodies for this endpoint. Mostly seen with older servers and some proxies/load balancers.
Make your client send Content-Length (disable chunked transfer encoding for this request).
Server-side note: Disable chunked encoding for this request so the client sends Content-Length.
The fastest way to pin down a 411 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.