Playing on cracked servers can be volatile. It is highly recommended to if you are playing with more than 3-4 people, as the "Host" feature within the game client can lead to high lag for the host.
If you only want to play with one or two friends and don't want to manage IP addresses, you can simulate local split-screen over the internet. Download a tool called or use Parsec . The host launches the cracked game. how to play multiplayer in cracked project zomboid install
Do not try to launch the game through a steam emulator if you are not using a dedicated server program. Launch it via the ProjectZomboid64.exe found in the root folder. Playing on cracked servers can be volatile