我收到 Nodejs 错误 EPERM：3000 的原因是什么？

Question

I'm deploying my node.js ts application on ubuntu server

app.js file listening to port 3000

var port = 3000
app
    .use(authRoutes_1.default.routes())
    .use(keysRoutes_1.default.routes())
    .use(exchangesRoutes_1.default.routes())
    .use(wishlistRoutes_1.default.routes())
    .listen(port, function () {
      console.log('Listening on port ' + port);
    });

When i approach my domen through browser i get an error listen eperm 3000

Then i created another one simple server listener js file with the following code

var http = require('http');
var server = http.createServer(function(req, res) {
  res.writeHead(200, { 'Content-Type': 'text/plain' });
  res.end('Hello World!');
});
server.listen(3000);

And suprisingly it works perfectly well

Another funny thing that running both files from ubuntu using node app.js throws the same EPERM error

How to solve this puzzle?

Answer 1

It seems like port 3000 is already used by another process. Can you try something like sudo lsof -i -P -n | grep LISTEN sudo lsof -i -P -n | grep LISTEN to check if there is any other process using that port? Or can you try change to another port to see if your node server works?