TeleportService:TeleportToPrivateServer() not working. How do i fix?

my problem is, is that it wont reserve the server. I don't know how to fix this, but I checked the dev wiki and i didn't see a mistake. Heres the code, I really hope you can help.

while wait() do
    if game.ReplicatedStorage.SoloPlayers.Value == 2 then
        if tpsolo.Value == false then
            tpsolo = true
            local key = ts:ReserveServer(3210889612) --error here
            local players = {}
            for i, v in pairs(game.ReplicatedStorage.SoloPlayers:GetChildren()) do
                local plr = game.Players[v.Value]
                table.insert(players, plr)
            end
            wait(.15)
            ts:TeleportToPrivateServer(3210889612, key, players)
            wait(1.5)
            tpsolo = false
        end
    end
end