My TweenSize Health Gui ServerScript does not work?

I did this in server script because if I do it in Local it wont show for to other people but it won't work im pretty sure everything here is defined correctly why won't it wokr?

Billboard = script.Parent
Redness = Billboard.REDNess
Greeness = Redness.GreenESS
TextLabel = script.Parent.TextLabel

Hum = script.Parent.Parent.Parent:WaitForChild('Humanoid')

Hum.HealthChanged:Connect(function(HP)
    Greeness:TweenSize(UDim2.new(HP/Hum.MaxHealth,0,1,0))
end)