My script is a d20 roll and it should pop the given number result above the player’s head but when running it the second time this error message pops up
local D20Event = game.ReplicatedStorage.D20Event
D20Event.OnServerEvent:Connect(function(plr)
for z = 0, 20 do
local a = math.random(1, 20)
game.StarterPlayer.StarterCharacterScripts.GUI.Parent = plr.Character.Head
plr.Character.Head.GUI.Number.Text = a
end
end)