421 Misdirected Request
4xx Client Error
RFC 9110
You sent this to the right address, but the wrong server.
What 421 Misdirected Request means {#what}
The server that received the request is not configured to produce a response for the requested scheme/host combination. Common in HTTP/2 connection reuse scenarios where a connection is shared across multiple origins.
When you’ll see a 421 {#when}
- HTTP/2 connection coalescing gone wrong
- Misconfigured reverse proxies handling multiple virtual hosts