HTTP 444 No Response is a non-standard status code used by Nginx to instruct the server to close the connection without sending a response. This is used to block malicious or unwanted requests — the client receives a connection reset instead of an HTTP response.
An Nginx configuration rule is deliberately returning 444 to drop the connection for matching requests (e.g., bots, scanners, specific IPs).
A Web Application Firewall or security rule is configured to silently drop suspicious requests.
Look for 'return 444' directives in the Nginx configuration to see which requests are being blocked.
nginx -T | grep 'return 444'
Review Nginx access logs to see which requests are getting 444 responses.
If you are a legitimate user, check if your IP, User-Agent, or request pattern matches a blocking rule.