Issue emitting socket.io messages on Ubuntu droplet

I recently moved my API:s from Heroku to a Ubuntu droplet provided by digital ocean. I followed these instructions on how to deploy my Node.js/Express API:s and got all of my endpoints working as expected. The only issue is that im able to connect/disconnect to the socket, but not able to emit any messages through the websockets. Everything works fine locally & in heroku with the same code, so I think the issue might be with nginx or ufw firewall.

Client code:

    const socket = socketIOClient(https://www.myapp.com/api-with-websockets);
    socket.connect();
    socket.emit('joinChannel', conversation.id);

Backend:

io.on("connection", (socket) => {
  console.log("New client connected");

  socket.on("joinChannel", (msg) => {
    console.log("New client joined channel:", msg); // <-- never gets called
    socket.join(msg);
  });

  socket.on("disconnect", () => {
    console.log("Client disconnected");
  });
});

nginx conf:

server {

        root /var/www/myapp.com/html;
        index index.html index.htm index.nginx-debian.html;

        server_name myapp.com www.myapp.com;

        location / {
                try_files $uri $uri/ =404;
        }

        location /api-with-websockets/ {
          proxy_pass http://localhost:3001/;
          proxy_http_version 1.1;
          proxy_set_header Upgrade $http_upgrade;
          proxy_set_header Connection 'upgrade';
          proxy_set_header Host $host;
          proxy_cache_bypass $http_upgrade;

        }


    location /no-websockets-api/ {
        proxy_pass http://localhost:3003/;
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection 'upgrade';
        proxy_set_header Host $host;
        proxy_cache_bypass $http_upgrade;
    }

    location ~ ^/(socket\.io) {
        proxy_pass http://localhost:3001;
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection 'upgrade';
        proxy_set_header Host $host;
        proxy_cache_bypass $http_upgrade;
    }


    listen [::]:443 ssl ipv6only=on; # managed by Certbot
    listen 443 ssl; # managed by Certbot
    ssl_certificate /etc/letsencrypt/live/myapp.com/fullchain.pem; # managed by Certbot
    ssl_certificate_key /etc/letsencrypt/live/myapp.com/privkey.pem; # managed by Certbot
    include /etc/letsencrypt/options-ssl-nginx.conf; # managed by Certbot
    ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem; # managed by Certbot


}
server {
    if ($host = www.myapp.com) {
        return 301 https://$host$request_uri;
    } # managed by Certbot


    if ($host = myapp.com) {
        return 301 https://$host$request_uri;
    } # managed by Certbot


        listen 80;
        listen [::]:80;

        server_name myapp.com www.myapp.com;
    return 404; # managed by Certbot

}