It looks like you're trying to open the HTML file directly from disc, but it seems you need to run them on a webserver in order for them to work. Most likely because it uses some server-side scripting that browsers will not load (for security reasons) when opened locally.
The Potree "Getting Started" page has some information on that. Basically you'll need to set up a local webserver, e.g. Apache through the XAMPP project, then place the HTML file in its htdocs directory and navigate to it via localhost. Hope this helps.
Thanks. I'll try that now. I had expected to see something locally and was using that for troubleshooting before pushing to AWS.