444 🌐 HTTP

Nginx 444 No Response (connection closed without response)

An Nginx-specific code: the server deliberately closed the connection without sending anything — a rule is dropping the request.

Seen on: REST API

Meaning

Nginx’s return 444 closes the connection silently. Admins use it to drop bots, requests with unknown Host headers, or blocked IPs. The client never sees “444”; it sees an empty reply (curl: (52) Empty reply from server, browser ERR_EMPTY_RESPONSE). You only find 444 in the Nginx access log.

Common causes

  • default_server block returning 444 for unknown Host headers
  • Security rule dropping bots, user agents or IPs
  • Fail2ban/WAF integration using 444
  • Request matched a deny location

⚡ Quick fix

  1. Search the Nginx config for return 444
  2. Call the site with the correct Host header/domain
  3. Check whether your IP or user agent is blocked

Detailed fix by platform

Nginx

  1. nginx
    sudo grep -rn 'return 444' /etc/nginx/
# typical catch-all that causes it:
server { listen 80 default_server; server_name _; return 444; }

curl

  1. curl -v -H 'Host: www.example.com' http://SERVER_IP/

How to diagnose

  1. Access log — Status 444 for these requests?
  2. Host — Does the Host header match a server_name?
  3. Rules — IP/UA deny rules

🔧 Still not fixed?

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

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