Why is my Model Placer script working only in ROBLOX Studio and not in game?

I am currently wondering why is a LocalScript working perfectly in Studio, but does nothing in the game itself.

The LocalScript itself:

lp = script.Parent
local debounce = false

function onButton1Down(mouse)

if not debounce then
    debounce = true
    local grenade = game.ServerStorage:WaitForChild("Grenade")
    local model = grenade:clone()
    model.Parent = game.Workspace
    model = game.Workspace:WaitForChild("Grenade")
    model.PrimaryPart = model.Union
    model:MakeJoints()
    model:MoveTo(mouse.hit.p)
    local cframe = model.PrimaryPart.CFrame
    model:SetPrimaryPartCFrame(cframe * CFrame.fromEulerAnglesXYZ(math.random(0,359), math.random(0,359), math.random(0,359)))
    wait(5)
    debounce = false
    end
end

function onEquipped(mouse)
    mouse.Button1Down:connect(function() onButton1Down(mouse) end)
end

lp.Equipped:connect(onEquipped)

The Script is in a Tool and it is supposed to clone a Model called Grenade from ServerStorage to Workspace where the mouse cursor is.

It works without any problems in ROBLOX Studio. However, when I join the game and use the Tool, it does nothing when I click.

As you can see, it is a LocalScript and there is WaitForChild here. It still works perfectly in ROBLOX Studio, but not in the game.

I kindly request your help and advice, fellow scripters.

Thanks.