Every time I press play I get that error. I have a GUI in PlayerGui named "Menu"
The script:
while wait() do
for _, v in pairs(game.Players:GetChildren()) do
local cont = v.PlayerGui.Menu.Container
cont.GoldVal.Text = v.leaderstats.Gold.Value
cont.LevelVal.Text = v.leaderstats.Level.Value
end
end
Error output:
22:55:30.705 - Menu is not a valid member of PlayerGui
22:55:30.707 - Stack Begin
22:55:30.708 - Script 'ServerScriptService.Script', Line 3
22:55:30.709 - Stack End

4 comments
It seems that Menu isn't a child of PlayerGui just saying I'm not that good at scripting
Ew don't do it like that. 1. Don't use wait() as a condition. 2. Don't use GetChildren, use GetPlayers. 3. Disregard the last 2 because you shouldn't even be doing it like that. Just update the text on the client using a Changed event.
The reason your script does not work is because you used a server script. The "Menu" ScreenGui was clones locally into the PlayerGui, the server doesn't see it.
if you have FE enabled you have to use an event to fire to all the clients from the serverside, see tutorials on remote events