eclipse-vertx/vert.x · error

511 Network Authentication Required (RFC6585)

Error message

511 Network Authentication Required (RFC6585)

What it means

Constant defining the 511 Network Authentication Required response expectation: applying expecting(SC_NETWORK_AUTHENTICATION_REQUIRED) makes a 511 response fail the request future. The client must authenticate to gain network access (captive portal); the 'message' is the reason on the failed future.

Source

Thrown at vertx-core/src/main/java/io/vertx/core/http/HttpResponseExpectation.java:335

  /**
   * 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}.
   *
   * @param statusCode the expected status code
   */
  static HttpResponseExpectation status(int statusCode) {
    return status(statusCode, statusCode + 1);
  }

  static HttpResponseExpectation status(int min, int max) {
    return new HttpResponseExpectation() {
      @Override
      public boolean test(HttpResponseHead value) {
        int sc = value.statusCode();
        return sc >= min && sc < max;
      }

View on GitHub (pinned to fb308bd8c3)

Solutions

1. Handle the failure by guiding the user through network authentication
2. Do not treat 511 as a service outage

When it happens

Trigger: Thrown at vertx-core/src/main/java/io/vertx/core/http/HttpResponseExpectation.java:335 when the library encounters an invalid state.

Common situations: See trigger scenarios.

Understand the failure class

• Authentication and authorization failures — expired tokens, bad credentials, and missing scopes.

AI-assisted analysis of eclipse-vertx/vert.x@fb308bd8c3 (2026-09-06). Data as JSON: /api/errors/32c9ed9b1f01c0aa. Report an issue: GitHub.