No colors in exported WEB Game

Godot Version

4.3

Question

Hi, I found this awesome mini-game (GitHub - KenneyNL/Starter-Kit-3D-Platformer: Godot). I tried to export it to WEB but the game is completely grey, no colors at all:

Could someone have a look on what make this game not convertible to WEB? Maybe I should replace some nodes/meshes/shaders etc?