HA alongside other web domain - SSL question

I have HAOS running on a co.uk domain, and a separate .com domain hosted on a nginx web server (on an Ubuntu VM). Both VM’s are on Proxmox.

I am using nginx on the Ubuntu web server to forward proxy requests to the HAOS domain, so:

  • My HAOS host is at 192.168.1.225:8123
  • My niginx server is at 192.168.1.36
  • My HA domain name is home.domain1.co.uk
  • My other web domain name is domain2.com
  • My router has ports 80 and 443 forwarded to 192.168.1.36
  • I have copied my SSL certs for home.domain1.co.uk from my HAOS host to /etc/letsencrypt/live/home.domain1.co.uk

This is my home.domain1.co.uk file (in the sites-available folder on 192.168.1.36):

server {
    listen 443 ssl;
    listen [::]:443 ssl;   
    ssl_certificate /etc/letsencrypt/live/home.domain1.co.uk/fullchain.pem;
    ssl_certificate_key /etc/letsencrypt/live/home.domain1.co.uk/privkey.pem; 
    server_name  home.domain1.co.uk;
    location / {
        proxy_pass https://192.168.1.225:8123/;
        proxy_set_header Host $host;
    }
    location /api/websocket {
        proxy_pass https://192.168.1.225:8123/api/websocket;
        proxy_set_header Host $host;
    }
}

Everything seems to be working, but I’m unclear which SSL certs are being used for my HAOS domain - the ones on the nginx host. or the ones on the nginx host?
The reason I need to know is so that I know how to renew them - they were created on the HAOS host, using the Let’s Encrypt add-in.
Now that port 80 is being forwarded to the nginx server (not the HAOS server), does this mean that I can no longer use the Let’s Encrypt add-in to update the SSL certs when they expire? If so, what would be the best way to renew them automatically?

The easiest way to tell which ssl cert is being used is to click the lock icon in your browser. Once you click on it you can see all the important about the cert such as which domain the cert was assigned to. If that doesn’t work you should see something called a serial number which is a unique number assigned to each cert.