How to create websocket conection?

I have node.js, express.js app width websocket

I create app platform

I have this client code:

let form = document.querySelector(".form");
let messagesDiv = document.getElementById("messages");
let formArea = document.querySelector(".form__area");

let sendMessage = () => {
    let formData = new FormData(form);
    let formDataValue = formData.get("text"); // Получаем значение конкретного поля, например "text"

    console.log("Отправляем значение:", formDataValue);

    if (socket.readyState === WebSocket.OPEN) {
        socket.send(formDataValue); // Отправляем только значение поля
        formArea.value = "";
    } else {
        console.log("WebSocket not connected");
    }
}

form.addEventListener("submit", (e) => {
    e.preventDefault();
    sendMessage();
});

formArea.addEventListener("keydown", (e) => {
    if (e.key === "Enter" && !e.shiftKey) {
        e.preventDefault();
        sendMessage();
    }
});

const url = 'ws://localhost:7000';
const socket = new WebSocket(url);

socket.onmessage = (e) => {
    console.log('Received data:', e.data);

    let messageElement = document.createElement('p');
    messageElement.textContent = e.data;

    messagesDiv.appendChild(messageElement);
}

socket.onopen = (e) => {
    console.log("WebSocket connection established");
}

And this server code:

import { WebSocketServer } from 'ws';

const run = async () => {
    const wss = new WebSocketServer({ port: 7000 });

    const clients = new Set();

    wss.on('connection', (ws) => {
        console.log('Client connected!');
        clients.add(ws);

        ws.on('message', (data) => {
            // Преобразуем данные в строку
            const message = typeof data === 'string' ? data : data.toString();
            console.log('Received data:', message);

            // Отправляем данные обратно всем подключённым клиентам
            clients.forEach(client => {
                if (client.readyState === WebSocket.OPEN) {
                    client.send(message);
                }
            });
        });

        ws.on('close', () => {
            console.log('Client disconnected');
            clients.delete(ws);
        });
    });

    console.log('WebSocket server is running on ws://localhost:7000');
};

export default run;

But, after deploy console write “WebSocket connection failed”

Why? What should i do?