for example, socket.io cannot be linked under a different wifi (ip address (under the public network). If my computer is connected to the 4G used on the wifi, phone, it cannot be connected (page resources and so on are completely fine, but the socket is not connected). If the computer and mobile phone are connected to a wifi, it is no problem. The server uses ubuntu and nginx, but if I try another, heroku will have no problem with the server he has configured, so I think it should be the problem with nginx

this is my nginx config:

upstream dirtyfinger {
    ip_hash;
    server localhost:3000;
    server localhost:3001;
    server localhost:3002;
    server localhost:3003;
}
server {
    listen 80;
    location / {
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection "upgrade";
        proxy_pass http://dirtyfinger;
    }
}