No Dynamic Shadows

Garry’s Mod doesn’t create dynamic shadows.

Dynamic shadows are created when you’re pointing your flashlight (or a lamp from the lamp tool) at an object. It will caste a shadow behind it by using the range, brightness, width and angles of the light source.
Normally this shouldn’t be a big problem when you’re just playing the game.

However I love making scenes with ragdolls that are doing things. The best way to finish this scene is by using appropriate lighting (which is best done by using the lamp tool and disabling the regular shadows with the command r_shadowcolor 255 255 255.) This command never affected dynamic shadows as I’m doing this for months now. I’ve been searching over the internet to look for fixes. I did come across this post on Steam where someone had the exact same problem as I did:

That solution did work for the OP but it didn’t work for me and I really want to get this problem fixed.

Is there anyone who can help me? Thanks in advance!