Most problems with a Barotrauma server come down to a few causes. Start with the one that matches what you see.
Players are told the game version is incompatible, or the server vanishes from their list after a Barotrauma update
Why: Client and server must be on the same major, minor and build version. If Auto Update is off, the server stays on the old build.
Fix: Restart the server so it updates. If you turned Auto Update off, turn it back on first. Players should be fully updated through Steam.
The server does not show up in the in-game server list
Why: List Publicly is off by default. The server browser also has a same-version filter that is ticked by default, which hides servers on a different version.
Fix: Turn on List Publicly (set a join password first if you want to control who joins), restart, and check your game version matches the server. Players can always use direct join with the Server Address instead.
Direct join does nothing, flashes the name box or says the address is invalid
Why: The game needs a player name entered before it opens direct join, and the address must be in the form address:port.
Fix: Type your player name in the name box, then paste the full Server Address from the Overview page, including the colon and port.
A change to the name or password made in the panel is not showing in the game
Why: Server Name and Join Password are only read when the server starts.
Fix: Restart the server after changing them.
Edits made by hand to serversettings.xml disappear
Why: The game saves its settings back to the file when it shuts down, so edits made while it was running are overwritten. The name, password, public listing and player limit set in the panel also replace the file's values at each start.
Fix: Stop the server, edit serversettings.xml, save, then start the server. Use the panel for name, password, listing and player limit.
Players with mods cannot join, or are told they are missing content
Why: Everyone needs the same content packs as the server, in a compatible version. Mods from the Workshop that were updated recently can differ between player and server.
Fix: Share the exact list of Workshop IDs with players, restart the server so it pulls current versions, and have players update their subscribed mods. Enter IDs as numbers separated by commas with no spaces.
Max Players cannot be changed or is lower than expected
Why: The limit comes from your plan and is read-only.
Fix: Use Players on the server Overview page to lower it (this restarts your server), or upgrade your plan to raise the limit.
Still stuck?
Open a ticket in the category that fits and include the last 50 to 100 lines of the console. See How to open a support ticket and How to fix a server that will not start.
