Why is my charging script breaking when it passes below 30?

i tried to make a script that reduces energy when you attack. I made it decreases if 30 and stops if the player has below 30 energy;but, when the energy goes below 30 it makes players not attack anymore, why?

 tool = script.Parent
PunchEvent = game.Workspace.Attacks["Rico's Attacks"].Punch
replicatedstorage = game:GetService("ReplicatedStorage")
staticball = replicatedstorage.RicoClass:findFirstChild("Lightning")
cooldown = false



tool.Selected:connect(function(mouse)
mouse.Button1Down:connect(function()

if not cooldown then
    cooldown = true
    local player = game.Players.LocalPlayer

    local Energy = player.PlayerGui.ScreenGui.TextButton.TextBox.EnergyValue
    game:WaitForChild(player)

    if Energy.Value >= 30 then --------------------------checks player's energy
        Energy.Value = Energy.Value - 30 -------------decreases player's energy


    local player = game.Players.LocalPlayer
    local Humanoid = player.Character.Humanoid
---------------------------------------------------------------------------------
        local Punch = Instance.new("Animation")
        Punch.AnimationId = "http://www.roblox.com/Asset?ID=644505212"
        local animTrack = Humanoid:LoadAnimation(Punch) 
            animTrack:Play(0,2,2.5)
---------------------------------------------------------------------------------   
PunchEvent:FireServer(mouse.Hit)
wait(0.4)
cooldown = false

end
end

end)
end)