Cloudflare Error 525
Critical
SSL handshake failed
Cloudflare failed to negotiate a successful SSL/TLS handshake with the origin server.
Impact: Website completely inaccessible
Responsibility
Configuration
This error is usually caused by incorrect DNS, SSL, or firewall configurations.
Common Causes
- Origin has no SSL certificate configured, but Cloudflare encryption mode is "Full" or "Strict"
- Origin only supports deprecated TLS versions
- SNI configuration mismatch
Troubleshooting Guide
1
Check Cloudflare SSL/TLS Mode
If the origin only supports HTTP (port 80), change Cloudflare SSL mode to "Flexible". If the origin has a self-signed certificate, use "Full". If it has a trusted CA certificate, use "Full (strict)".