Why am I getting the output 'Cannot store Array in DataStore'?

I've been trying to test out DataStore, but I keep getting this error. It refers to both the saving and the loading script. It works fine in-game (saving to a value, loading from it), but it doesn't save to the DataStore, so the stats don't remain for the next time it's played.

I looked over the lines output referred to, but I couldn't figure it out. Could someone help me find out what's wrong with it?

Also, is there a better way to save data to DataStore than saving when the player leaves? Preferably on a button's mouseclick?

The saving script:

local DataStore = game:GetService("DataStoreService"):GetDataStore("PDS")

game.Players.PlayerRemoving:connect(function(player)
	
	local key = "player_" ..player.userId
	
	
	local valuesToSave = {player.leaderstats.Level.Value, player.GameInfo.Experience.Value, player.GameInfo.Coins.Value, player.GameInfo.Color.Value, player.GameInfo.SaveData.Value}
	DataStore:SetAsync(key, valuesToSave)
	
end)

The loading script:

local DataStore = game:GetService("DataStoreService"):GetDataStore("PDS")

game.Players.PlayerAdded:connect(function(player)
	repeat wait() until player.Character
	
	local stats = Instance.new("IntValue", player)
	stats.Name = "leaderstats"
	
	local level = Instance.new("IntValue", stats)
	level.Name = "Level"
	
	local gameinfo = Instance.new("IntValue", player)
	gameinfo.Name = "GameInfo"
	
	local xp = Instance.new("NumberValue", gameinfo)
	xp.Name = "Experience"
	
	local coins = Instance.new("NumberValue", gameinfo)
	coins.Name = "Coins"
	
	local color = Instance.new("BrickColorValue", gameinfo)
	color.Name = "Color"
	
	local gamedata = Instance.new("BoolValue", gameinfo)
	gamedata.Name = "SaveData"
	
	local key = "player_" ..player.userId
	
	local savedValues = DataStore:GetAsync(key)
	
	if savedValues then
		-- Save Format: {level, xp, coins, color, data}
		level.Value = savedValues[1]
		xp.Value = savedValues[2]
		coins.Value = savedValues[3]
		color.Value = savedValues[4]
		gamedata.Value = savedValues[5]
	else
		local valuesToSave = {level.Value, xp.Value, coins.Value, color.Value, gamedata.Value}
		DataStore:SetAsync(key, valuesToSave)
	end
	
end)

Thanks in advance!

EDIT: I also got an output about HTTP 404.