Why is this value being called as "nil" even though I defined it?

Hello, I made a script where if the round ends teleports all the players to the lobby spawns. I defined everything but can't seem to find an issue. It gives me and error.

error:

16:06:24.217 - ServerScriptService.MainScript:364: attempt to get length of global 'lobbyspawns' (a nil value)

here is the section of script that matters

	-- Teleport players back to lobby and remove tools.
	lobbyspawns = {}
	for _, v in pairs(game.Workspace:WaitForChild("Lobby"):GetChildren()) do
		if v ~= nil and v.Name == "SpawnLocation" then
			table.insert(lobbyspawns, v)
		end
		print (#lobbyspawns)
	end
end
for _, player in pairs(aliveplayers)do
	if player ~= nil then
		awardpoints(player, 2)
		if player.Character ~= nil then
			local humanoid = player.Character:FindFirstChild("Humanoid")
			if humanoid ~= nil then
				humanoid:UnequipTools()
			end
		end
		local randomspawn = lobbyspawns[math.random(1, #lobbyspawns)]
		print(#lobbyspawns)
		player.Character:MoveTo(randomspawn.Position)
		local backpack = player:FindFirstChild("Backpack")-- Remove tools.
		if backpack ~= nil then
			backpack:ClearAllChildren()
		end
	end
end

the lobby name is "Lobby" and the children are names SpawnLocation. however when I try to teleport them it doesn't work and a got that error.

How can I get this to work?

Its most likely because of choosing random spawns. Maybe, if you assign everyone numbers (added when they join, and when someone leaves the server other numbers change to correct themselves, Example: player joins, is first in server so number is 1, the next player joins with 2, and another player joins, with the number 3. the player with number 2 leaves. player 3 will become number 2.) Assign all the number to different spawns and that might work.

Your issue resides on that very first line. Unfortunately, you don't give enough information to know what the issue is exactly (It resides in the code before what is shown) however if the lobbyspawns is within a while loop, for ... in loop or if statement, you'll need to check your condition because it's not evaluating to true and therefore your code is skipping the assignment of lobbyspawns