HTTP 505 — HTTP Version Not Supported
5xx Server Error
What it means
The server does not support the HTTP protocol version the client used.
What to do about it
Rare. Usually a misconfigured client or an old proxy speaking HTTP/0.9.
Where it sits
505 belongs to the 5xx family: The server failed to fulfil an apparently valid request. The fix is on the server side.
HTTP/1.1 505 HTTP Version Not SupportedChecking it yourself
# see the status code and headers only
curl -sI https://example.com/path
# follow redirects and print each hop
curl -sIL -o /dev/null -w "%{http_code} %{url_effective}\n" https://example.com/path
# JavaScript
const r = await fetch(url);
console.log(r.status, r.statusText);