"invalid key type used" error?

I'm getting an error which is resulting in my teleporting not functioning. Any ideas?

SCRIPT IN SERVERSCRIPTSERVICE

local access = teleportService:ReserveServer(player2Game)
local players = {player}
for i,friend in pairs(friendsOnline) do
	if friend.PlaceId == game.PlaceId and friend.GameId == game.JobId then
		local friendPLR = game.Players:FindFirstChild(friend.UserName)
		game.Workspace.friendSend:FireAllClients(friendPLR,player)
		game.Workspace.friendSend.onServerEvent:Connect(function(suspectPLR)
			if suspectPLR == friendPLR then
				players[i] = game.Players:FindFirstChild(friend.UserName)
			end
		end)
	end
end
wait(4.5)
teleportService:TeleportToPrivateServer(player2Game,access,players)

LOCALSCRIPT IN STARTERPLAYERSCRIPTS

repeat wait() until game.Players.LocalPlayer
game.Workspace.sendFriend.OnClientEvent:Connect(function(player,sent)
	if game.Players.LocalPlayer == player then
		local clone = game.ReplicatedStorage.JoinB:Clone()
		clone.Parent = player.PlayerGui.Priiv
		clone.label.Text = sent.Name.." is starting a room!"
		wait(4)
		if clone.Value.Value == "string" then
			clone:Destroy()
			player.PlayerGui.Priiv.Enabled = false
			game.Workspace.sendFriend:FireServer()
		end
	end
end)