If you look at the browser console, you can see that you need to configure CORS headers if you want to serve files from other origins than your page.
See Cors warning on hosted build using loadsync function - #3 by hybridherbst for a more complete explanation.
If you’re unable to configure those headers on your hosting solution, I recommend hosting the splat/ply file in the same place as your web app – for example, you can put it locally into the include folder and load it from a relative path:
