Factorio refuses a player when their game and the server run different versions: every player needs exactly the same version and mods as the server (Factorio wiki, Multiplayer). Most often the player's game updated and the server has not restarted since. Restart the server so it updates, then join again.
Fix it
- Open your server in the panel and click Restart.
- In the Console, read the
[pnh-update]line:Updated to Factorio ...or... is already installed. Note the version. - Ask the player to check their own version and update their game to the same one.
- Join again once the Console shows
Hosting game at.
Type /version in the Console to see the server's version at any time.
Why is the server behind?
- It has not restarted since the update. The server only updates when it starts. The Daily restart schedule does that every morning: How to restart your Factorio server on a schedule.
- Updates are off or the version is held. The Console says
Automatic updates are offorFactorio is pinned to .... Switch Auto-update server on, or set Factorio Version tolatest: How to update your Factorio server. - factorio.com could not be reached. The Console says
WARNING could not read a stable headless version from factorio.com. Keeping the installed build.Restart again a little later.
Why is the server ahead?
- It runs experimental. Factorio Version is
experimental, and the player is on stable. Either the player switches to the same experimental version, or you go back tolatest: How to switch your Factorio server to the experimental version. - The player held their game back, for example to keep old mods. They update to the server's version.
- Nintendo Switch players. Cross-platform play works only when versions match, the Switch has no mods, and games on a dedicated server are not shown in the Switch's browse lists (Factorio wiki).
If the versions match and the player still cannot join, check mods and Space Age: Players get a mod mismatch when joining your Factorio server.
