Sentora does not run on Nginx... so either you have a custom install or something completely changed on your server.
Code:
Welcome to nginx!
If you see this page, the nginx web server is successfully installed and working. Further configuration is required.
For online documentation and support please refer to [url=http://nginx.org/]nginx.org[/url].
Commercial support is available at [url=http://nginx.com/]nginx.com[/url].
[i]Thank you for using nginx.[/i]