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HTTP/5xx (Server Error)

511 Network Authentication Required

The client needs to authenticate to gain network access.

❓ Why does this happen?

Captive portals on hotel, airport, or café Wi-Fi intercept requests until you accept the terms.

✅ How to fix it

Open any http:// page in the browser to trigger the captive portal login, then retry.

Return or handle 511 in your stack

// app/api/resource/route.ts
export function GET() {
  return Response.json(
    { error: "Network Authentication Required", status: 511 },
    {
      status: 511
    }
  );
}

Live 511 mock endpoint

Point your app, tests, or retry logic at this free public URL to reproduce a real 511 response (CORS enabled, optional ?delay=ms up to 5000).

https://castov.com/api/mock/511

Frequently Asked Questions

What does HTTP Status 511 mean?
The client needs to authenticate to gain network access.
Why am I getting a 511 status code?
Captive portals on hotel, airport, or café Wi-Fi intercept requests until you accept the terms.
How do I fix a 511 Network Authentication Required error?
Open any http:// page in the browser to trigger the captive portal login, then retry.
How can I test how my app handles a 511 response?
Send a request to https://castov.com/api/mock/511 — it returns a real 511 Network Authentication Required response with CORS enabled. Add ?delay=2000 to simulate a slow server.

Other 5xx status codes

500501502503504505507508511520521522523524525526

Browse the full HTTP status codes directory or troubleshoot terminal errors in the Error Fix Encyclopedia.