Got 500 error when deploying Next.js to Google Cloud - google-app-engine

Question

I deployed a next.js application to the App Engine Standard and I get 500 error. In StackDriver the error is "/bin/sh: 1: server.js: not found"
but server.js exists in the app:
I'm serving up my project on port 3000
Package.json is like this:
{
"name": "supplychain",
"version": "1.0.0",
"description": "",
"main": "index.js",
"scripts": {
"test": "mocha",
"dev": "node server.js",
"start": "NODE_ENV=production server.js",
"transpile": "babel src -d dist --copy-files",
"prepublishOnly": "npm run transpile",
"build": "next build",
"deploy": "gh-pages -d examples/dist",
},
"author": "",
"license": "ISC",
"dependencies": {
"#babel/polyfill": "^7.2.5",
"fs-extra": "^7.0.1",
"ganache-cli": "^6.4.1",
"mocha": "^5.2.0",
"next": "^4.1.1",
"next-routes": "^1.4.2",
"radium": "^0.25.1",
"react": "^16.8.4",
"react-dom": "^16.8.4",
"semantic-ui-react": "^0.82.5",
"solc": "^0.4.25",
"truffle-hdwallet-provider": "0.0.3",
"web3": "^1.0.0-beta.35"
},
"devDependencies": {
"#babel/cli": "^7.2.3",
"#babel/core": "^7.2.2",
"#babel/preset-env": "^7.3.1",
"babel": "^6.23.0",
"babel-cli": "^6.26.0",
"babel-preset-es2015": "^6.24.1",
"css-loader": "^2.1.0",
"html-webpack-plugin": "^3.2.0",
"npm-install-webpack-plugin": "^4.0.5",
"terser-webpack-plugin": "^1.3.0",
"uglifyjs-webpack-plugin": "v1.0.0-beta.1",
"webpack": "^4.35.0",
"webpack-cli": "^3.3.4",
"webpack-dev-server": "^3.7.2"
}
}
and app.yaml is like:
# [START app_yaml]
runtime: nodejs8
# [END app_yaml]
Can somebody help me find the problem?

Answer 1

Change this line:
"start": "NODE_ENV=production server.js",
To:
"start": "NODE_ENV=production node server.js",