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HTTP 306 — (Unused)

HTTP 306
(Unused)
A reserved code that was used in an old draft and is now permanently unassigned.

What 306 actually means

This number was allocated to a proposal called "Switch Proxy" in an early HTTP/1.1 draft and dropped before the specification was finished. It is reserved so nothing else can claim it, and it has no meaning. A server sending a 306 is broken or lying; clients treat it as they would any unrecognised 3xx, which means the same as 300.

Common causes

  • A non-conforming server or a deliberately malformed response
  • A test suite or fuzzer exercising unusual status codes

If you're just trying to view the page

  1. Nothing you can do — the server is sending an invalid response
  2. Try the site again later or contact its owner

If it's your site

  1. Never emit 306; pick a real code from the registry
  2. Clients should treat an unrecognised 3xx as a generic 300 and not follow anything automatically

Reference

Status code
306
Reason phrase
(Unused)
Category
3xx — Redirection
Defined in
RFC 9110 §15.4.7

Common questions

What does HTTP 306 mean?
A reserved code that was used in an old draft and is now permanently unassigned. This number was allocated to a proposal called "Switch Proxy" in an early HTTP/1.1 draft and dropped before the specification was finished. It is reserved so nothing else can claim it, and it has no meaning.
How do I fix a 306 error?
Nothing you can do — the server is sending an invalid response
Is 306 a client error or a server error?
306 is in the 3xx range, which means redirection. It is not an error at all.

Related pages

Sources

  1. Hypertext Transfer Protocol (HTTP) Status Code Registry — IANA
  2. RFC 9110: HTTP Semantics — IETF

How these figures are compiled and checked