HTTP 421 Misdirected Request means the request was directed at a server that is not able to produce a response for the target URI. This can occur with HTTP/2 connection coalescing when a client reuses a connection for a domain whose certificate does not cover the requested hostname.
Status
421 Misdirected RequestExample
GET /page HTTP/1.1
Host: www.example.com
User-Agent: Mozilla/5.0
Accept: text/htmlHTTP/1.1 421 Misdirected Request
Content-Type: text/html; charset=utf-8
<!doctype html>
<html>
<body>
<h1>421 Misdirected Request</h1>
<p>This server is not configured to handle requests for this address.</p>
</body>
</html>How to Troubleshoot
Check SSL certificate coverage
Verify the server's TLS certificate covers the requested hostname (check Subject Alternative Names).
openssl s_client -connect example.com:443 -servername example.com 2>/dev/null | openssl x509 -noout -text | grep DNS:
Check virtual host configuration
Ensure the server has a virtual host configured for the requested domain.
Common Causes
HTTP/2 connection coalescing mismatch
highThe client reused an HTTP/2 connection for a hostname not covered by the server's TLS certificate.
Misconfigured virtual hosts
mediumThe server does not have a virtual host configured for the requested hostname.
Quick Diagnostics
Related Status Codes
References
| Specification | Section |
|---|---|
| HTTP Semantics | RFC 9110 §15.5.20 |
Frequently Asked Questions
This reference was compiled from official RFCs, protocol specifications, and hands-on troubleshooting experience. AI tools were used primarily for formatting and organizing the content on the page.