I have managed to resolve the issue by switch off the "proxy to apache" in the "Nginx and apache setting" options. I would like to share information here. 1. we should not concern the Nodejs listen port because it is taken by  by passenger plugin.  Nodejs will auto listen on unix socket and communication.  it will skip the port setting. 2. we have to switch off the "proxy to apache". so Nginx will proxy all requests to Nodejs.   😀