Multisite NGINX configuration with subdomains


I am stuck on configuring nginx with multisite. I have 2 sites one should be on (main site) and 1 on I successfully set up the installation on the main site - and in the admin created new site configuration for as matching hostname. I then configured to use a reverse proxy in nginx to but that just gives me 504 Gateway timeout default nginx error page.

The nginx config on the subdomain is like this:

location / {

Is there some documentation on this or is someone able to provide a hint as to what I need to change in my config?

The main page works. It’s just the subdomain that does not.

Any help is appreciated. Thank you.