socket.io 没有连接 reactjs nodejs

io 没有连接 reactjs nodejs"/>

socket.io 没有连接 reactjs nodejs

服务器：

    const io = socketio(server, {
        cors: {
            origin: "",
            methods: ["GET", "POST"],
            credentials: true
        },
        transports: ['websocket', 'polling'],
        allowEIO3: true
    });```

client:

让 connectionOptions = { “强制新连接”：是的， "reconnectionAttempts": "无限", “超时”：10000， “传输”：[“websocket”，“轮询”]， }; const ws = new io(url, connectionOptions);

in browser its saying connection failed

i want connect socket.io with reactjs and nodejs backeend i am usingg apche ubuntu