No errors When Player Humanoid dead and respawns not working??

I found a few errors on the script also you need to put a wait in there when the humanoid has 100 health because when the humanoid is still respawning the Gui goes visible. Here is the fixed script put it in serverscriptservice.

local Players = game:GetService("Players")

game.Players.PlayerAdded:Connect(function(Player)

    Player.CharacterAdded:Connect(function(Char)

        Char.Humanoid.Died:Connect(function()

            if Char.Humanoid.MaxHealth == 100 then-- majour error you forgot to do MaxHealth

                wait(4)-- if you want to change this make the number greater than 4 because it takes about 3. something seconds to fully respawn 

                Player.PlayerGui.MainUI.Enabled = true

                Player.PlayerGui.MoneyGui.Enabled = true

                end

        end)

    end)

end)

Hope this helps!!