nodeJS spawn child_process doesn't work on glitch.com

I want to serve an express server on glitch.com with the following code:

const path = require('path');
const { spawn } = require('child_process');
const express = require('express');

const app = express();
app.use(express.static('public'));

const defaultServerPath = path.join(__dirname, 'default/index.js');
const defaultServerProcess = spawn('node', [defaultServerPath], { env: { PORT: 4000 } });

defaultServerProcess.on('exit', (code) => {
  console.log(`Der erste Server wurde mit dem Code ${code} beendet!`);
});

const roomServerPath = path.join(__dirname, 'room/index.js');
const roomServerProcess = spawn('node', [roomServerPath], { env: { PORT: 5000 } });

roomServerProcess.on('exit', (code) => {
  console.log(`Der zweite Server wurde mit dem Code ${code} beendet!`);
});

const port = process.env.PORT || 3000;
app.listen(port, () => {
  console.log(`Reverse proxy server running on ${port}`);
});

It works locally by running the script with node index.js or npm run start but not on glitch.

I get this error message on https://glitch.com/. app@indigo-midi-sushi:~ 08:54 $ npm run start

> express-socket_chatroom@1.0.0 start /app
> nodemon index.js

[nodemon] 2.0.22
[nodemon] to restart at any time, enter `rs`
[nodemon] watching path(s): *.*
[nodemon] watching extensions: js,mjs,json
[nodemon] starting `node index.js`
events.js:174
      throw er; // Unhandled 'error' event
      ^

Error: spawn node ENOENT
    at Process.ChildProcess._handle.onexit (internal/child_process.js:240:19)
    at onErrorNT (internal/child_process.js:415:16)
    at process._tickCallback (internal/process/next_tick.js:63:19)
    at Function.Module.runMain (internal/modules/cjs/loader.js:834:11)
    at startup (internal/bootstrap/node.js:283:19)
    at bootstrapNodeJSCore (internal/bootstrap/node.js:623:3)
Emitted 'error' event at:
    at Process.ChildProcess._handle.onexit (internal/child_process.js:246:12)
    at onErrorNT (internal/child_process.js:415:16)
    [... lines matching original stack trace ...]
    at bootstrapNodeJSCore (internal/bootstrap/node.js:623:3)
[nodemon] app crashed - waiting for file changes before starting...

I know that the spawning of the processes causes the error, but why? spawn('node', [], { env: { PORT: }

Turns out you cannot expose more than one port on glitch.