506 Variant Also Negotiates

What is HTTP 506?

This status code indicates that the server has an internal configuration error: the chosen variant resource is itself configured to engage in content negotiation, creating a circular reference. Transparent content negotiation requires that the endpoints in the negotiation set do not themselves negotiate. This is a server misconfiguration and the server operator needs to fix the negotiation setup.

Defined in RFC 2295

Common Causes

• A variant resource in the negotiation set is incorrectly configured to also negotiate content
• Circular references in transparent content negotiation configuration
• Misconfigured server content negotiation rules creating an infinite loop

How to Fix

• Review the server's content negotiation configuration and remove circular references
• Ensure that variant resources resolve to final representations, not further negotiations
• Simplify content negotiation rules to avoid self-referencing variants