In version 4.3, I tried all the solutions, but none of them worked. Eventually, I found the problem: the light object placed in the middle of the scene doesn’t work. The light must be in front of the Grease Pencil object for it to work. So, you need to adjust the Y-axis position.
Hi there. I would recommend using Blender version 4.2 LTS (the latest bug fix version is 4.2.4 and is very stable) to do these exercises. Blender 4.3 has had a massive upgrade to Grease Pencil and alot gets handled a bit differently. I hope to release a quick video explaining some of the changes in the new year, but for best results, I'd advise using Blender 4.2