Make sure you and your friends are running the same game version. You can check for updates in the game's settings menu or on the Ubisoft website.
Ensure every player uses the Ubisoft Connect/Steam "Verify Files" tool. A single corrupted texture or mismatched mod file will trigger an instant desync. anno 1800 lan multiplayer fixed
Here is the definitive tested method for a 2-4 player local game with zero internet dependency: Make sure you and your friends are running
The host should load the save alone in a single-player session. A single corrupted texture or mismatched mod file
does not officially support an offline LAN mode; an active internet connection and login to Ubisoft Connect are required to initiate multiplayer sessions
| 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. |