A button script works in Studio, but not in actual ROBLOX. Its a nil value? {UPDATE}

I was recently working on a class selection GUI, and I encountered this problem. "Thompson" is a nil value. Ive never had this problem before. The thing is, it works in Studio but then it errors inside actual ROBLOX?

Heres the code, Ill also link some picture to Imgur that give a more info in case you need it :)

player = game.Players.LocalPlayer
button = script.Parent.Play

button.MouseButton1Click:connect(function()
	local Thompson = game.Workspace.Guns:findFirstChild("Thompson")
	Thompson:clone().Parent = player.Backpack
	Thompson:clone().Parent = player.StarterGear
	player.HasClass.Value = true
	script.Parent.Visible = false
end)

You'll have to manually copy the link

https://imgur.com/FnlC69V

^Shows were it is in Explorer

https://imgur.com/7FkZMyy

^Shows the error inside actual ROBLOX

Thanks and I hope somoene may be able to figure this out :)

ADDON - I tried using, Lighting, Replicated Storage and Server Storage. Lighting and Replicated storage work but then the gun just falls through the map and doesnt stay in the hand. Its weirdd

ADDON 2 - It works when FE is turned off but it doesnt work with FE turned on? Any new ideas?

1. Make sure "Thompson" is in the Guns folder
2. Use "ReplicatedStorage" to hold any items you want to clone. So move the "Guns" from workspace to ReplicatedStorage

Theres an easier way to clone things in coding, such as using this :

local player = game.Players.LocalPlayer
local button = script.Parent.Play
local rep = game:GetService("ReplicatedStorage")

button.MouseButton1Click:Connect(function()
rep.Guns:FindFirstChild("Thompson"):Clone().Parent = player.Backpack
player.HasClass.Value = true
script.Parent.Visible = false
end)

You was changing the parent of the gun, 2 times. Starterpack and Startergear, which i never heard of startergear.

What i wrote should work, if any errors feel free to comment.

Try using a local script if your not already using one.