ECONNREFUSED during pre-rendering

I am running stencil build --prerender. My app fetches data from a static JSON file in the assets directory called “model.json.” When I build my app as normal, there are no issues; the JSON file is fetched and rendered by the component which consumes it. However, when using pre-render, the build fails with the following error:

[ /  error ]  FetchError: request to http://localhost:3334/assets/model.json failed, reason: connect ECONNREFUSED ::1:3334

Has anybody else experienced this issue?