Help with light flicker?

I have this script where it makes a light look like it is flickering and I am getting this error: Workspace.Lights.Model.Model2.Light.Flicker:11: bad argument #2 to 'random' (interval is empty)

SpotLight = script.Parent:WaitForChild("Light").SpotLight
Light1 = script.Parent.Part1
Light2 = script.Parent.Part2
Light3 = script.Parent.Part3
Light4 = script.Parent.Part4
Light5 = script.Parent.Part5
Light6 = script.Parent.Part6


while true do
	wait(math.random(.6,.1))
	SpotLight.Enabled = false
	Light1.Material = "SmoothPlastic"
	Light2.Material = "SmoothPlastic"
	Light3.Material = "SmoothPlastic"
	Light4.Material = "SmoothPlastic"
	Light5.Material = "SmoothPlastic"
	Light6.Material = "SmoothPlastic"
	wait(math.random(.6,1.3))
	SpotLight.Enabled = true
	Light1.Material = "Neon"
	Light2.Material = "Neon"
	Light3.Material = "Neon"
	Light4.Material = "Neon"
	Light5.Material = "Neon"
	Light6.Material = "Neon"
	
end