What it means
Transparent content negotiation is misconfigured: the chosen variant is itself set up to negotiate, creating a loop.
Common causes
- A server configuration error with content negotiation (RFC 2295)
How to fix it
As a client or visitor
Nothing you can fix; contact the site owner.
As the site or API owner
Fix the variant configuration so the selected representation is not itself negotiable.
Example response
HTTP/1.1
HTTP/1.1 506 Variant Also Negotiates
Date: Tue, 07 Oct 2025 09:30:00 GMT
Server: nginx
Content-Length: 0Specification
FAQ
› Is 506 common?
Very rare; it requires experimental transparent content negotiation.
› Which servers produce 506?
Mostly Apache with mod_negotiation misconfigurations.