| Error Code | Meaning | The LAN Fix | | :--- | :--- | :--- | | | Relay server timeout | Switch to Direct Connection . The host is trying to use Ubisoft servers. | | Desync (CTD) | Packet loss | Check your Ethernet cables. Disable WiFi on both PCs if hardwired. | | "Unable to join" | Port 18000 blocked | Manually forward ports OR disable Windows Defender entirely for 5 mins to test. | | Endless Loading | IPv6 conflict | Disable IPv6 on your Network Adapter properties. Force IPv4. |
Here is the definitive tested method for a 2-4 player local game with zero internet dependency:
The question on everyone's lips is finally being answered: anno 1800 lan multiplayer fixed
Unlike older strategy titles, Anno 1800 does not feature a pure, offline offline-only LAN mode. It uses a hybrid peer-to-peer (P2P) architecture that requires validation through Ubisoft Connect servers.
Anno 1800 relies on specific network ports to transmit game data between players. If your router blocks these ports, LAN connections will fail. Access your router's gateway page to open the following ports: | Error Code | Meaning | The LAN
: Many players find that disabling IPv6 on their network adapter resolves the "unable to connect" error, especially when playing across different Windows versions.
: Ensure your NAT type is "Open." If it is "Unknown" or "Strict," check for interference from third-party security software like F-Secure or Kaspersky. You may also need to open relevant ports in your Windows Firewall 2. Resolving Desyncs and LR40 Errors Disable WiFi on both PCs if hardwired
Launch the game; Ubisoft Connect will automatically regenerate clean versions of these files. 6. How to Correctly Host and Load a Multiplayer Save
Right-click the Windows Start button and select or Command Prompt (Admin) .