Getting PM2 Error Script not found

I deploy strapi on my dedicated server with MySQL database, for virtual host setting I set up Nginx service.
I have followed this documentation to setup How to deploy a Strapi Project on Ubuntu 16.04
Things are working fine but for automatic script execution I install PM2 on my server, but when I run NODE_ENV=production pm2 start server.js, PM2 through me an error script not found.

My server.js is below

module.exports = ({ env }) => ({
host: env(‘HOST’,‘’),
admin: {
auth: {
secret: env(‘ADMIN_JWT_SECRET’, ‘21d82785f17dc8a3845cc115696b7f75e’),

Any Idea ?