Articles & Guides

Cloudflare error 525 SSL Handshake Failed means the TLS handshake with the origin failed. Check the origin certificate, use openssl s_client, and fix SSL modes.

Cloudflare error 522 Connection Timed Out means your origin server did not answer in time. Diagnose the origin, check the firewall, use curl, and fix it.

DNS_PROBE_FINISHED_NXDOMAIN means a domain will not resolve. Step-by-step diagnosis, dig and nslookup commands, plus DNS cache flush on Windows, macOS, Linux.

ERR_CONNECTION_RESET means the connection was dropped midway. Learn the causes of a TCP reset, diagnose with curl and traceroute, and fix it step by step.

ERR_SSL_PROTOCOL_ERROR is a failed SSL/TLS handshake. Learn the causes, diagnose with openssl and curl, and fix the certificate and protocol step by step.

ERR_NAME_NOT_RESOLVED means the browser couldn't turn the domain into an IP. Learn the DNS causes, diagnose with nslookup and dig, and fix it step by step.

"This site can't be reached" is a generic Chrome error. A diagnostic checklist: DNS, ping, curl, cache clearing, and step-by-step client and server fixes.

ERR_TOO_MANY_REDIRECTS means the site is stuck in a redirect loop. Learn the causes, trace it with curl -sIL, and fix HTTPS, www, and cookie issues fast.

ERR_CONNECTION_TIMED_OUT means the server never replied in time. Learn the causes, diagnose with ping and traceroute, and fix it on both client and server.

ERR_CONNECTION_REFUSED means the server actively refused the TCP connection. Learn the causes, diagnose with curl and ping, and fix it step by step quickly.