HTTP Status Codes

421 Misdirected Request

The request was routed to a server that cannot respond for the target authority — often an HTTP/2 connection-coalescing mismatch across hostnames sharing a certificate.

What it means

421 Misdirected Request arises when a connection is reused (via HTTP/2 coalescing) for a hostname the server is not configured to serve, even though the TLS certificate covers it. The client should retry the request on a fresh, dedicated connection.

Why it matters

  • It lets clients recover from HTTP/2 coalescing by re-establishing a correct connection.

Common mistakes

  • Certificates covering many hostnames while backends are not all configured to serve them.

How WebInspect checks this

  • WebInspect reports HTTP version, ALPN and certificate SANs relevant to connection coalescing.