Can't connect to node HTTP server running on localhost

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6

I have configured my package.json with this:

  "scripts": {
    "build": "gatsby build",
    "start": "gatsby serve",
    ...
  }

So first the build is run, which produces static HTML/CSS/JS, then gatsby serve just spins an HTTP server serving those assets from localhost:9000. As the screenshot above shows, that command starts fine: “Running on port 9000”.