The "connection refused" message is from the Server Side Rendering. The problem is like this:
- Volto nodejs server wants to generate an HTML for your browser to load. It tries to connect to Plone and fetch the content, so that the generated HTML is already showing you the proper content.
- Now your browser will load the generated HTML and then execute the Javascript that is Volto running in your browser. That Javascript will connect to the Plone backend and it will load and redisplay the content. This process is called hydration.
So, what happens is that you briefly see the HTML produced by the server, then the client-side app loads. For some reason the server is unable to connect to the Plone backend.