Overhead Gui is not working and no errors are being displayed, can anyone see whats wrong with it?

--Main Variables-- 
BillboardGui = script.Parent.BillboardGui

--Services--
Players = game:GetService('Players')

--Settings-- 
Visitors = {83997127, 3242545, 3423455}
EventManagement = {3242545, 3423455}

MaxOverheadDistance = 25

--Core--

function checkUserId(Player)
    for _,v in pairs(Visitors) do
        if type(v) == "number" and v == Player.UserId then
            return 'Honoured Visitor'
        end
    end
    for _,v in pairs(EventManagement) do
            if type(v) == "number" and v == Player.UserId then
                return 'Event Management'
            end
        end
    return nil
end

Players.PlayerAdded:Connect(function(Player)
    Player.CharacterAdded:Connect(function(Character)
        local BG = BillboardGui:Clone()
        BG.Parent = Character:WaitForChild('Head')
        BG.Player.Text = Player.Name
        BG.MaxDistance = MaxOverheadDistance;
        if checkUserId(Player) ~= nil then
            BG.Position.Text = checkUserId(Player) 
        end
    end)
end)

I am not entirely sure if this will work, but let me know if any errors come up.

Use LocalScript

local players = game.Players.LocalPlayer or game.Players.PlayerAdded:Wait()
local BillboardGui = script.Parent.BillboardGui
local Visitors = {83997127,3242545,3423455} -- Don't add "" when u use Numbers
local EventManagement = {3242545, 3423455} -- Don't add "" when u use Numbers
local MaxOverheadDistance = 25
wait()
for i, v in pairs(Visitors) do
    if players.UserId == v then
    BillboardGui:Clone().Parent = workspace:FindFirstChild(players.Name).Head
    BillboardGui.Player.Text = players.Name
    BillboardGui.Position.Text = "Honoured Visitor"
    BillboardGui.MaxDistance = MaxOverheadDistance
    end
end

Consider changing the beginnings of the constants put 'local' into it.

--Variables-- local BillboardGui = script.Parent.BillboardGui

--Settings-- local Visitors = {"83997127", "3242545", "3423455"} --Put user ids here that are visitors local EventManagement = {"TESTID", "3242545", "3423455"} --Put the user ids here that are managing the event local MaxOverheadDistance = 25 --Sets how far you can see the overhead gui above players

--Core-- game.Players.PlayerAdded:Connect(function(players) for i, v in pairs(Visitors) do if (players.UserId == v) then BillboardGui:Clone(); BillboardGui.Player.Text = player.Name; BillboardGui.Position.Text = "Honoured Visitor"; BillboardGui.MaxDistance = MaxOverheadDistance; BillboardGui.Parent = game.Workspace:WaitForChild(players.UserId) end end

end