HTTP 506 Variant Also Negotiates (RFC 2295) indicates that transparent content negotiation for the request results in a circular reference — the server's chosen variant is itself configured to engage in content negotiation, creating an infinite loop. This is a server configuration error, not a client error. It's extremely rare in practice and indicates a misconfigured content negotiation setup.
Response includes the status code, standard headers (including Content-Type), and a small diagnostic JSON body describing the request and returned status.
Simulator URL (copy in the app after load — not a normal link):
https://httpstatus.com/api/status/506
Example request:
curl -i "https://httpstatus.com/api/status/506"