LW 4.9 introduced an auto firewall detector. If you don't have your OSX firewall turned on, then the issue is most likely your modem/router. Personally I needed to manually port forward mine. But the newer ones have UPnP but some need to be enabled. See Connection problems? Check here first! But also check to see if you have your OSX firewall turned on. If yes, then you'll need to make an exception for LW.