Browser security errors › Chrome and Edge
ERR_SSL_PROTOCOL_ERROR: how to fix it on your website
The browser and server could not complete a TLS handshake.
What your visitors see
The page will not load at all, with 'This site can't provide a secure connection'.
Common causes
- Server not actually speaking TLS on port 443
- Only old protocols such as TLS 1.0 enabled
- Broken certificate or key configuration
- Firewall or proxy interfering
How to fix it
- Enable TLS 1.2 and 1.3 on the server
- Confirm port 443 is configured for SSL (for Nginx: listen 443 ssl)
- Test with: openssl s_client -connect yourdomain.com:443
- Check CDN SSL mode, for example Cloudflare Full (strict) with a valid origin certificate
Check your certificate and TLS setup
Korrali Web scans your site for certificate, TLS and security header problems and can monitor it so you hear about expiry before visitors do.