How do i make color changing text gui's?

I have this script that i'm pretty sure is right but, it wont work when i test run the game. Does anyone know what i did wrong?

while true do
	script.Parent.TextColor3 = Color3.fromRGB(255, 85, 0)
	wait(0.5)
	
	script.Parent.TextColor3 = Color3.fromRGB(170, 0, 0)
	wait(0.5)
end