Change ports for DigitalOcean Agent

I tried to test the DigitalOcean Agent from this link [https://www.digitalocean.com/community/tutorials/how-to-install-and-use-the-digitalocean-agent-for-additional-droplet-graphs].

I have successfully installed. When I see Graph beta, the message show “No data available for this metric”. As I know, DigitalOcean Agent uses ports 80 and 443 for outgoing data. Unfortunately I also use 80 and 443 on nginx as the following configuration.

server {
  listen 80;
  server_name myserver.com;
  return 301 https://$host$request_uri;
}

server {

    # SSL configuration
    listen 443 ssl http2 default_server;
    listen [::]:443 ssl http2 default_server;
    ssl on;

    server_name myserver.com;

    ssl_certificate ...;
    ssl_certificate_key ...;

    location / {
        proxy_pass http://localhost:8181;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;
    }

   location ^~ /.well-known/ {
       allow all;
   }

   access_log /var/log/nginx/access.log combined;
}

I would like to know how can I change these two ports for DigitalOcean Agent to use other ports. Thanks.