You can detect Nginx Default Page using this tool.
NGINX is a free, open-source, high-performance HTTP server and reverse proxy, as well as an IMAP/POP3 proxy server. NGINX is known for its high performance, stability, rich feature set, simple configuration, and low resource consumption.
The remote web server uses the default Nginx index page. This page may contain some sensitive data like the server root and installation paths. This could potentially leak useful information about the server installation to a remote, unauthenticated attacker.
Disable server tokens. Review the files and replace or delete as needed.