526 Invalid SSL Certificate

526

Invalid SSL Certificate

Example HTTP Response

HTTP Response

HTTP/1.1 526 Invalid SSL Certificate
Server: cloudflare
Content-Type: text/html

<html><body>Invalid SSL certificate</body></html>

Common Causes

Origin SSL certificate is expired
Origin uses self-signed certificate with Full (Strict) mode
Certificate Common Name/SAN doesn't match hostname
Certificate chain is incomplete or broken
Certificate was revoked
Certificate signed by untrusted CA
Cloudflare SSL/TLS mode set to Full (Strict) inappropriately

Technical Details

What does this mean?

Your credentials are bogus! Cloudflare checked your origin's SSL certificate and it's either fake, expired, or signed by someone sketchy. No secure connection for you!

Technical Definition

Cloudflare could not validate the SSL certificate on the origin server when in Full (Strict) SSL mode.

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(526).json({
    error: 'Invalid SSL Certificate',
    message: 'Your error message here'
  });
});

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

http.createServer((req, res) => {
  res.writeHead(526, { 'Content-Type': 'application/json' });
  res.end(JSON.stringify({
    error: 'Invalid SSL Certificate',
    message: 'Your error message here'
  }));
}).listen(3000);

Related Status Codes

🎫495SSL Certificate Error 🔐525SSL Handshake Failed

526 Invalid SSL Certificate FAQ

What causes a 526 Invalid SSL Certificate error?

Origin SSL certificate is expired. Origin uses self-signed certificate with Full (Strict) mode. Certificate Common Name/SAN doesn't match hostname. Certificate chain is incomplete or broken. Certificate was revoked. Certificate signed by untrusted CA. Cloudflare SSL/TLS mode set to Full (Strict) inappropriately.

// Express.js app.get('/example', (req, res) => { res.status(526).json({ error: 'Invalid SSL Certificate', message: 'Your error message here' }); }); // Native HTTP const http = require('http'); http.createServer((req, res) => { res.writeHead(526, { 'Content-Type': 'application/json' }); res.end(JSON.stringify({ error: 'Invalid SSL Certificate', message: 'Your error message here' })); }).listen(3000);

526 Invalid SSL Certificate FAQ

What causes a 526 Invalid SSL Certificate error?