Trouble assigning CollisionGroups

[blockydiamond01 (PapaTeddy)]

So I am trying to make a player and an npc non-collide. Here is my script there are no errors:

game.Players.PlayerAdded:Connect(function(plr)
	local npcGroup = "NPCS"
	local playerGroup = "WeThePeople"
	
	PhysicsService:RegisterCollisionGroup(npcGroup)
	PhysicsService:RegisterCollisionGroup(playerGroup)
	PhysicsService:CollisionGroupSetCollidable(npcGroup, playerGroup, false)
	
	for i, v in pairs(NPCS:GetDescendants()) do
		if v:IsA'BasePart' then
			v.CollisionGroup = npcGroup
		end
	end
	
	for i, v in game.Players:GetDescendants() do
		if v:IsA'BasePart' then
			v.CollisionGroup = playerGroup
		end
	end
end

[Starviing (Starving)]

Instead of getting the Descendants of players, do GetDescendants on the character when its added. You should also register the Collision Groups outside, so we dont do it everytime a new player gets added. Same for the Npcs, they dont need to be added each time a player gets added all over again. If Npcs gets spawned in and such, you can check if a child has been added to the npc folder and then add them to the collisiongroup.

local npcGroup = "NPCS"
local playerGroup = "WeThePeople"
	
PhysicsService:RegisterCollisionGroup(npcGroup)
PhysicsService:RegisterCollisionGroup(playerGroup)
PhysicsService:CollisionGroupSetCollidable(npcGroup, playerGroup, false)

	for i, v in pairs(NPCS:GetDescendants()) do
		if v:IsA'BasePart' then
			v.CollisionGroup = npcGroup
		end
	end

game.Players.PlayerAdded:Connect(function(plr)
plr.CharacterAdded:Connect(function(character)
	
	for i, v in character:GetDescendants() do
		if v:IsA'BasePart' then
			v.CollisionGroup = playerGroup
		end
	end
end)
end)