HaruHost1. Same version as the game
After a Palworld update, players can't join a server that is still on the old version. Press Update on the server, or let an automation update it as soon as Palworld releases an update.
2. Windows Firewall
On Windows, turn on Auto-manage Firewall in Settings → Network and HaruHost adds firewall rules for the server's ports every time it starts. Its firewall check finds missing rules, and a Windows network set to Public, which blocks game traffic. Fix repairs both.
3. The router
Each server gets its own ports from your port range, so one forwarding rule on the router covers every server you run. HaruHost shows the rule to add and links your router's page. On Windows, HaruHost can also open the ports on your router automatically (UPnP) every time the server starts. See port forwarding.
4. A public address
Some internet connections (CGNAT, Starlink, mobile data, many apartment networks) give you no public address, so no router setting helps. Turn on the Tunnel and friends join through HaruHost's relay instead.
Something else is using the port
On Windows, if another program holds the server's port, HaruHost stops the start and tells you which port, instead of starting a server nobody can reach.
Questions
Why does Palworld say "connection timed out"?
The server can't be reached from the player's side. Most often the router isn't forwarding the port, Windows Firewall blocks it, or the internet connection has no public address. The checks on this page cover each one; the Tunnel avoids all three.
Can my friends connect but I can't?
Use the Local Address under Advanced on the Details tab. Many routers can't reach their own public address from inside the house.