Plutonium

We tried disabling any anti-virus, firewalls or any other 3rd party software (windows defender included) but still no luck. We also tried using LogMeIn Hamachi and for just moment I could join one of my friends but now we are back to nothing working properly.

When my friends try to load in my custom games (not zombies, just normal games) they just get a loading animation saying "connecting" but nothing ever happens.

We have tried double clicking each others names while someone is in a custom game to join them and also using the "connect [ip]" method through the consoles.

UPnP is enabled in all our devices. Do we have to try port forwarding or something similar or is there some other problem?

Thank you in advance.