Attempted to index a nil value?

I get the following error when I try to update the display that tells the player how much money they have:

19:15:32.798 - ServerScriptService.DataManager:47: attempt to index field '?' (a nil value)
19:15:32.798 - Stack Begin
19:15:32.799 - Script 'ServerScriptService.DataManager', Line 47
19:15:32.800 - Stack End

Script inside the serverscriptservice:

local DS = game:GetService("DataStoreService")
local Players = game:GetService("Players")
local Run = game:GetService("RunService")

local playerDataStore = DS:GetDataStore("PlayerData")

local PlayerSesStats = {} -----Player data on current session
local LoadedPlayers = {} -----Players whose data has already been loaded

local UpdEve = game.ReplicatedStorage.UpdateCash

local function DefaultStats()
	return {
		Money = 100
	}
end

local function UpdateCash(player, amount)
	UpdEve:FireClient(player, amount)
end

local function GuestCheck(player) -----Checks wether or not the player is a Guest
	return Run:IsStudio() and player.UserId < 1
end

local function OnPlayerAdded(player)
	
	local userid = player.UserId
	
	if LoadedPlayers[userid] then -----Checks wether or not the user's data has been loaded on the current server
		player:Kick("An error occured when attempting to fetch your player data. Please wait a few seconds and rejoin.")
		return
	end
	
	if not GuestCheck(player) then
		local loadSuccess, LoadedData = pcall(function() return playerDataStore:GetAsync(player.UserId) end) ----- Returns the player's datastore and wether or not it succeeded in that.
		
	if loadSuccess and LoadedData then
		if LoadedData == nil or LoadedData == {} then
			PlayerSesStats[player.UserId] = DefaultStats()
		else 
			PlayerSesStats[player.UserId] = LoadedData
		end		
	end
	end
	
	UpdateCash(player, PlayerSesStats[player.UserId].Money)
end
	
local function OnPlayerRemoved(player)
	if not LoadedPlayers[player.UserId] then
		return
	end
	
	local SaveData = PlayerSesStats[player.UserId]
	
	pcall(function()
		playerDataStore:SetAsync(player.UserId, SaveData)
	end)
	LoadedPlayers[player.UserId] = nil
end

local function OnServerShutdown()
	local Players = Players:GetPlayers()
	
	for index = 1, #Players do
		local player = Players[index]
		OnPlayerRemoved(player)
	end
end


Players.PlayerAdded:Connect(OnPlayerAdded)
Players.PlayerRemoving:Connect(OnPlayerRemoved)

game:BindToClose(OnServerShutdown)

The script that updates the player's currency display:

local Display = script.Parent.MainGui.CashBox.Cash
local UpdEve = game.ReplicatedStorage.UpdateCash

UpdEve.OnClientEvent:Connect(function(amount)
	Display.Text = amount
end)

What is causing the error and how do I fix it? And by the way, am I doing datascripts right so far?