"invalid argument #2 to 'random' (interval is empty)" problem?

Whenever I test-play my Hide and Seek game, I always see this error message appear: "invalid argument #2 to 'random' (interval is empty)". How do I solve this issue?

Full Code:

-- Services
local replicatedStorage = game:GetService("ReplicatedStorage")
local serverStorage = game:GetService("ServerStorage")

local status = replicatedStorage:WaitForChild("Values").Status

-- Config
local playersToStart = 1

-- Functions

local function chooseSeeker(availablePlayers)
    return availablePlayers[math.random(1, #availablePlayers)]
end

local function teleportPlayers(availablePlayers, spawns) -- availablePlayers: Table / spawns: Table
    for _, plr in pairs(availablePlayers) do
        if plr.Character then
            if plr.Character:FindFirstChild("HumanoidRootPart") then
                plr.Character.HumanoidRootPart.CFrame = spawns[math.random(1, #spawns)].CFrame + Vector3.new(0,5,6) <-- line with error message
            end
        end
    end
end

while wait(1) do

    repeat

        print("Not enough players in-game!")
        status.Value = playersToStart.." players or more are needed to start. (/"..playersToStart..")"

        wait(1)

    until #game.Players:GetPlayers() >= playersToStart

    for i = 5,0,-1 do
        status.Value = "Next round starts in "..i.." seconds."
        wait(0.1)
    end

    local contestants = game.Players:GetPlayers()

    local seeker = chooseSeeker(contestants)

    status.Value = "The chosen seeker is... "
    wait(2)
    status.Value = seeker.Name.."!"

    wait(3)

    local map = workspace.Map

    teleportPlayers(contestants, map.Spawns:GetChildren())
    wait(5)
end