eclipse-vertx/vert.x · error

506 Variant Also Negotiates (RFC2295)

Error message

506 Variant Also Negotiates (RFC2295)

What it means

Constant defining the 506 Variant Also Negotiates response expectation: with expecting(SC_VARIANT_ALSO_NEGOTIATES), a 506 response fails the request future. This indicates a server-internal Transparent Content Negotiation misconfiguration; the 'message' is the reason attached to the failure.

Source

Thrown at vertx-core/src/main/java/io/vertx/core/http/HttpResponseExpectation.java:320

  /**
   * 503 Service Unavailable
   */
  HttpResponseExpectation SC_SERVICE_UNAVAILABLE = status(503);

  /**
   * 504 Gateway Timeout
   */
  HttpResponseExpectation SC_GATEWAY_TIMEOUT = status(504);

  /**
   * 505 HTTP Version Not Supported
   */
  HttpResponseExpectation SC_HTTP_VERSION_NOT_SUPPORTED = status(505);

  /**
   * 506 Variant Also Negotiates (RFC2295)
   */
  HttpResponseExpectation SC_VARIANT_ALSO_NEGOTIATES = status(506);

  /**
   * 507 Insufficient Storage (WebDAV, RFC4918)
   */
  HttpResponseExpectation SC_INSUFFICIENT_STORAGE = status(507);

  /**
   * 510 Not Extended (RFC2774)
   */
  HttpResponseExpectation SC_NOT_EXTENDED = status(510);

  /**
   * 511 Network Authentication Required (RFC6585)
   */
  HttpResponseExpectation SC_NETWORK_AUTHENTICATION_REQUIRED = status(511);

  /**
   * Creates an expectation asserting that the status response code is equal to {@code statusCode}.

View on GitHub (pinned to fb308bd8c3)

Solutions

  1. Report the server-side TCN configuration error
  2. Bypass content negotiation for this resource
Defensive patterns

Strategy: try-catch

When it happens

Trigger: Thrown at vertx-core/src/main/java/io/vertx/core/http/HttpResponseExpectation.java:320 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of eclipse-vertx/vert.x@fb308bd8c3 (2026-09-06). Data as JSON: /api/errors/3965c0eecb07c66c. Report an issue: GitHub.