我是webdev的新手，我正在尝试用proxy_pass在nginx上部署一个express应用程序！
这个应用程序在我的机器上运行得很好，但是当我从nginx尝试时出现了连接错误。
下面是我的nginx配置：

http {
        include mime.types;

        server {
                listen                  80;
                root                    /var/www/sites;

                location /someapp/ {
                        proxy_pass      http://localhost:9999/;
                }

                location /someOtherApp/ {
                        proxy_pass      http://localhost:5173/;
                }

                location /theAppWithSocketIo/socket.io/ {
                        proxy_http_version      1.1;
                        proxy_set_header        X-Real-IP $remote_addr;
                        proxy_set_header        X-Forwarded-For $proxy_add_x_forwarded_for;
                        proxy_set_header        Host $http_host;
                        proxy_set_header        X-NginX-Proxy false;

                        proxy_pass              http://localhost:3000/socket.io/;
                        proxy_redirect          off;

                        proxy_set_header        Upgrade $http_upgrade;
                        proxy_set_header        Connection "upgrade";
                }

                location /theAppWithSocketIo/ {
                        proxy_pass      http://localhost:3000/;
                }
        }
}

客户代码：

"use strict";

var Socket = io(
    'http://<IPADRESS>',
    {
        path: '/<APPPATH>',
        rejectUnauthorized: false,
        extraHeaders: {
            token: document.cookie.split( "=" )[ 1 ]
        }
    }
);

Socket.on("connect_error", (err) => {
        console.log(`connect_error due to ${err}`);
    });

服务器代码：

const express = require("express");
const path = require("path");
const { createServer } = require("http");
const { Server } = require("socket.io");
const connectDB = require("./db");
const cors = require('cors');
const cookieParser = require("cookie-parser");

// Create Express Socket.io server
const app = express();
const whitelist = [<URLS>];
const corsOptions = {
    origin: (origin, callback) => {
        if (origin === undefined || whitelist.includes(origin)) {
            callback(null, true);
        } else {
            callback(new Error('Not allowed by CORS'));
        }
    },
    credentials: true
};
app.use(cors(corsOptions));
const httpServer = createServer(app);
const io = new Server(httpServer);

connectDB();

io.on("connection", socket => console.log('connected'));

app.use(express.json({ extended: false }));
app.use(cookieParser());
app.use(express.static(path.join(__dirname, '/')));

// Other Routes

const PORT = 3000; // config.get('PORT')

const listener = httpServer.listen(PORT, () => {
    console.log("Node.js listening on port " + listener.address().port);
});

客户端socket.io无法连接到服务器，我从Socket.on（'connect_error'）获得多个控制台日志，但它们对我帮助不大..// connect_error due to Error：伺服器错误
我查了一下https://socket.io/docs/v3/troubleshooting-connection-issues/我的ws请求是200，但他们从来没有到达服务器。在io.on（'连接'）的console.log从来没有得到调用。
任何帮助都是受欢迎的..我已经在这上面两天了..