Из-за чего я получаю ошибку Invalid Namespace при подключении к Socket.io Серверу?

location /socket.io/ {
                root /var/www/socket.io_service;
                proxy_pass http://localhost:3004;
                proxy_redirect off;
                proxy_http_version 1.1;

                proxy_set_header Upgrade $http_upgrade;
                proxy_set_header Connection "upgrade";
                proxy_set_header Host $host;
                proxy_set_header X-Real-Ip $remote_addr;
                proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        }

const io = require('socket.io-client')('http://my_server_ip/socket.io/')