easy beginner's script doesn't work cause of (a nil value) error..why this happens ?

server-sided script in serverscriptservice it say in the output that there is a proplem in line 3 attempt to index a local "char" (a nil value) it's sooo strange..that script should be very easy and it worked well before today !

game.Players.PlayerAdded:Connect(function(plr)
	local char = plr.Character
	local human = char.Humanoid
	human.WalkSpeed = 100
	
	end)

when i changed the script as this it worked again !!

game.Players.PlayerAdded:Connect(function(plr)
	local char = game.Workspace:WaitForChild("hmurban")
	local human = char.Humanoid
	human.WalkSpeed = 100
	
	end)

You need to make sure the character has loaded in. What's happening is that when the player joins, you're trying to access the player's character before it even gets a chance to exist.

To make this work we need to use this:

Players.CharacterAdded:Connect(function(character)

This runs the function when the character loads in. I'm not going to show you how to use it, I'm actually going to challenge you to try to make this work on your own. If you need help just ask in the comments.(I'm not sure if I'm allowed to do this :P)