Players on the newest game version cannot join your Enshrouded server

Restart your server. With Auto Update on, every start installs the newest server version. Everyone needs the same game version as the server, so a server left on an old version turns away players who updated.

Fix it

1. Open your server in the panel and click Restart.
2. Open the Console and wait for [Session] 'HostOnline' (up)!. A start after an update takes longer than usual.
3. Ask your players to try again.

If it still does not work

1. Check Auto Update. Click the Settings tab, Game Settings, then Show advanced (2). Auto Update must be on. If it was off, turn it on and restart.
2. Turn on Validate for one start and restart. It checks every server file against Steam, as part of the update, so Auto Update must be on too. Turn Validate off afterwards.
3. Read the Console while it starts. If it prints Update failed, retrying without the old build record, the server is repairing its files. Let it finish.
4. Ask the player to update their game in Steam, and to restart it. A player whose game did not update cannot join a server on the newest version either.

Keep it from happening again

The Daily restart schedule restarts the server early every morning and so picks up updates. See How to restart your Enshrouded server on a schedule and How to update your Enshrouded server.

If the problem stays, open a ticket with the last 50 lines of the Console.