421 Misdirected Request

421

Misdirected Request

Example HTTP Response

HTTP Response

HTTP/1.1 421 Misdirected Request

Common Causes

Request sent to wrong server in cluster
TLS certificate mismatch
HTTP/2 connection reuse issue

Technical Details

What does this mean?

Wrong door! You knocked on a server that can't help you with this particular request. Try another one!

Technical Definition

The request was directed at a server that is not able to produce a response.

RFC Says

"The 421 (Misdirected Request) status code indicates that the request was directed at a server that is not able to produce a response. This can be sent by a server that is not configured to produce responses for the combination of scheme and authority that are included in the request URI."

Plain English:

421 means 'You sent your request to the wrong server.' This is mainly relevant for HTTP/2 and HTTP/3 where connection reuse is common. It tells the client 'I received your request, but I'm not the right server to handle this domain/hostname - try connecting directly to the right server instead.'

Common Misinterpretation

This is specific to HTTP/2+ connection reuse scenarios. Don't use it in HTTP/1.1 APIs. It's for cases where a server handles multiple domains but can't handle this particular request due to TLS certificate issues or server configuration.

View RFC Documentation

Code Snippets

Ready-to-use code for returning this HTTP status in your application:

Node.js

// Express.js
app.get('/example', (req, res) => {
  res.status(421).json({
    error: 'Misdirected Request',
    message: 'Your error message here'
  });
});

// Native HTTP
const http = require('http');

http.createServer((req, res) => {
  res.writeHead(421, { 'Content-Type': 'application/json' });
  res.end(JSON.stringify({
    error: 'Misdirected Request',
    message: 'Your error message here'
  }));
}).listen(3000);

421 Misdirected Request FAQ

What causes a 421 Misdirected Request error?

Request sent to wrong server in cluster. TLS certificate mismatch. HTTP/2 connection reuse issue.

// Express.js app.get('/example', (req, res) => { res.status(421).json({ error: 'Misdirected Request', message: 'Your error message here' }); }); // Native HTTP const http = require('http'); http.createServer((req, res) => { res.writeHead(421, { 'Content-Type': 'application/json' }); res.end(JSON.stringify({ error: 'Misdirected Request', message: 'Your error message here' })); }).listen(3000);