@REX_DUNGEUR can you give me any more information? I tried it in Chrome (on desktop and mobile) and it works fine. Can you try opening the console and seeing if it prints any more information?
edit: the problem is your playground is version 4.2.0. This one requires the 5.0 alpha. I will see what I can do about it.
edit 2: fixed. https://playground.babylonjs.com/#WBEEFF#2