ServerScriptService.Main:77: attempt to concatenate field '?' (a nil value)?

My code works fine until I get to line 8, and it gives the error shown above. I have no idea how to fix this, and any help is appreciated. Please note this is not the full code.

for _, player in pairs(activecontestants) do
        if player and player.Character then
            local humanoid = player.Character:FindFirstChild("Humanoid")
            if humanoid then
                humanoid:UnequipTools()
                player.Backpack:ClearAllChildren()
                humanoid.Health = 100
                gameState.Value = "The winner(s) are " .. activecontestants[player.Name]
                local lobbyspawns = workspace:FindFirstChild("LobbySpawns"):GetChildren()
                player.Character:MoveTo(lobbyspawns[math.random(1, #lobbyspawns)].Position)
            end
        end
    end
end