Plutonium

Me and my friends have been playing WaW zombies and coop campaign before the t4 refactor update using Hamachi and doing the xpartygo + connect [IP] method which worked fine for any of us.
But since the t4 refactor update it is not longer possible for my friends to connect to my LAN lobby, i can connect just fine to my friends' lobbies and play any time we want, but when my friends try to connect to mine they just get an error saying "Failed to conenct". They can search the lobby and see any kind of changes i make to my lobby while seeing it on the servers list but they get that error.
For more information:
-None of us have touched any of our internet settings prior or after the update
-None of us have port forwarding or have touched any of our firewalls settings
-I am the only one that can't host