How to add second location for subdomain

I'm currently running a containerd analytics application on one of my ISPconfig servers which is working fine. The webinterface is proxied through nginx on a subdomain of a website running on the same server. Here my config:

Subdomain:
Host: stats
Domain: example.com
Redirect Type: Proxy
Redirect Path: HTTP 10.11.12.13:9999
Don't add to Let's Encrypt certificate: unchecked
Active: checked

Because the application requires several headers I set them in the options tab:

Code:

        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header Host $host;
        proxy_set_header X-Forwarded-Proto $scheme;
        proxy_redirect off;

Now because the app requires a connection via websocket to itself I'd like to add a second location to the nginx config like so:

Code:

    # WebSocket
    location /live/websocket {
        proxy_pass HTTP 10.11.12.13:9999;
        
        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-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;

        # Timeout
        proxy_read_timeout 3600s;
        proxy_send_timeout 3600s;
    }

This works fine if I edit the nginx config under /etc/nginx/sites-available manualy but gets overwirtten everytime changes are made to the parent site in ISPconfig. How do I configure this in ISPConfig itself?

Thanks for yor help.

 

I tried that but it didn't work.

The websocket is part of the site on the subdomain and not the parent website:

wss://stats.example.com/live/websocket?_csrf_token=CyUZOTsqZz4NHQk1WihdgfkjpoOpnZyhPlDgJX1maPPkQ4dOCw&_mounts=0&_live_referer=undefined&vsn=2.0.0