attempt to index nil with 'Gold'?

I'm making a tds game and i experienced an error.

I tried using :WaitForChild() but it gave me the same exact error.

function towerModule.attackMob(newTower, player)
	local config = newTower.Config
	local target = findNearestTarget(newTower, config.Range.Value)
	if target  and target:FindFirstChild('Zombie') and target.Zombie.Health > 0 then
		local targetCFrame = CFrame.lookAt(newTower.HumanoidRootPart.Position, target.HumanoidRootPart.Position)
		newTower.HumanoidRootPart.BodyGyro.CFrame = targetCFrame
		
		target.Zombie:TakeDamage(config.Damage.Value)
		if target.Zombie.Health <= 0 then
			player.Gold.Value += target.Zombie.MaxHealth
		end
		task.wait(config.Cooldown.Value)
	end
	task.wait(0.1)
	
	towerModule.attackMob(newTower)
end

I believe the code block is the reason why it's erroring.

But, here is the error that i am experiencing:

14:56:44.149 ServerScriptService../main../tower:32: attempt to index nil with 'Gold' - Server - ./tower:32 14:56:44.149 Stack Begin - Studio 14:56:44.149 Script 'ServerScriptService../main../tower', Line 32 - function attackMob - Studio - ./tower:32 14:56:44.149 ? Script 'ServerScriptService../main../tower', Line 38 - function attackMob (x49) - Studio - ./tower:38 14:56:44.152 Stack End

I would be very happy for solutions.