A 506 Variant Also Negotiates error is a webserver’s code for: "The server's internal content negotiation configuration is caught in an infinite loop.".

How do I fix or troubleshoot a 506 Error?

Common steps include reloading the page in your browser, checking for typos in the URL, verifying server status, clearing browser cache or cookies, and contacting the website owner or server administrator if the error persists.

506 Error | Error-Message.Net

A 506 Variant Also Negotiates error is an experimental HTTP status code (defined in RFC 2295) indicating that the server has an internal configuration error where the chosen variant resource is configured to engage in transparent content negotiation itself, creating a circular reference loop.

Content negotiation allows servers to deliver different versions of a file (such as English vs. Spanish, or WebP vs. JPEG) based on browser headers. If a variant points back to another negotiating variant, an infinite loop occurs.

Determining why

This is strictly a server-side configuration defect in the webserver’s transparent content negotiation rules (such as Apache’s mod_negotiation).

Steps you could possibly take:

If you are a visitor - There is nothing you can do locally. Contact the website owner to inform them of the server misconfiguration.
If you are the server administrator:
- Review your content negotiation directives in Apache (TypeConfig, AddType, or Multiviews).
- Ensure variants point to concrete static files rather than another negotiable resource.

Source: RFC 2295 Section 8.1 (Transparent Content Negotiation)