ERR_CONNECTION_CLOSED Browser Origin: On your device Last updated 15 Oct 2026

Chrome: This site can’t be reached — example.com unexpectedly closed the connection. ERR_CONNECTION_CLOSED

The server closed the connection before finishing the TLS handshake or sending a response — typical for HTTP/HTTPS port mix-ups, strict firewalls and crashing servers.

Exact message you may see unexpectedly closed the connection
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Seen on: Chrome Edge

Meaning

Compared with "connection reset" (an abrupt RST), "closed" means a clean close during setup. Frequent causes are requesting https:// from a port that serves plain HTTP (or the reverse), a server that only supports newer TLS, a WAF dropping unknown clients, and antivirus HTTPS scanning.

Common causes

  • Using https:// on a port that serves only HTTP (or http:// on an HTTPS-only port)
  • TLS version/cipher mismatch rejected by the server
  • Firewall/WAF closing connections silently
  • Antivirus or VPN interfering with TLS
  • Server overloaded or crashed

⚡ Quick fix

  1. Check the URL scheme and port
  2. Test with curl -v to see where it closes
  3. Try without VPN/antivirus web protection

Detailed fix by platform

Linux

  1. curl -v https://example.com and openssl s_client -connect example.com:443 -servername example.com show the handshake

Windows

  1. Temporarily disable "HTTPS scanning" in your antivirus; run netsh winsock reset

How to diagnose

  1. URL — Right scheme and port?
  2. Handshake — Where does openssl s_client stop?
  3. Software — Antivirus/VPN involved?

🔧 Still not fixed?

Many errors look alike. If the steps above didn’t solve it, one of these is probably what you’re facing:

Where this error sits

Origin: On your device. Errors that are often confused with or caused by this one (click to open):

525 — Cloudflare Error 525: SSL Handshake Failed (Cloudflare)525526 — Cloudflare Error 526: Invalid SSL Certificate (Cloudflare)526A TLS error caused the secure connection to fail — Safari: Safari Can’t Open the Page — A TLS error caused the secure connection to fail (Browser)A TLS error caused th…captive portal — Browser: This network requires you to sign in — captive portal (hotel, airport, café Wi-Fi) blocking HTTPS sites (Browser)captive portalDNS_PROBE_FINISHED_NO_INTERNET — Chrome: No internet — DNS_PROBE_FINISHED_NO_INTERNET (DNS probe finished, no internet) (Browser)DNS_PROBE_FINISHED_NO…DNS_PROBE_FINISHED_NXDOMAIN — Chrome: This site can’t be reached — server IP address could not be found. DNS_PROBE_FINISHED_NXDOMAIN (Browser)DNS_PROBE_FINISHED_NX…ERR_ADDRESS_UNREACHABLE — Chrome: This site can’t be reached — The webpage at https://… might be temporarily down. ERR_ADDRESS_UNREACHABLE (Browser)ERR_ADDRESS_UNREACHAB…ERR_CONNECTION_ABORTED — Chrome: The connection was aborted — ERR_CONNECTION_ABORTED (software on your computer caused it) (Browser)ERR_CONNECTION_ABORTEDERR_CONNE…

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