Why FireServer() Not Registering?

When I click on a imagebutton & then use :FireServer(), it doesn't work. Anyone know why?

Local Script:

Four1.MouseButton1Click(function()
	if FFour1.Value > 0 then
	else
		gridpos.Value = "Four1"
		game.ReplicatedStorage.PlaceBloxEvent:FireServer(purchaseid.Value, gridpos.Value)
	end
end)

Script:

local Four1 = script.Parent.One
game.ReplicatedStorage.PlaceBloxEvent.OnServerEvent:connect(function(player, purchaseid, gridpos)
	print(purchaseid)
	print(gridpos)
	if gridpos == "Four1" then
		if purchaseid == 1 then
			game.ReplicatedStorage.Models.RustyPrinter:Clone().Parent=Four1
			
		end
	end
end)

Is this because im using an imagebutton? I tried a Button & an Image Button.