Why does socket.io not found error occur when connecting?

Question

Node.js

I create a server in the index.js file in this way (I read in the official SOCKET.IO document that this can be done): In the client part, I connect like this: I address like this: Error 404:
var io = require('socket.io')(8000);
socket = io();
https://mysite.com/main

https://mysite.com/socket.io/?EIO=3&transport=polling&t=LwRdl0p

Answer 1

Telepaths are invited:
1. Node.js listens on port 8000, and the browser is accessing port 80.
2. socket on / main, and loading either at a different address
changes Nginx routes?