steam://connect link or a desktop shortcut fails with "app id specified by server is invalid".ASA. Since patch 32.24 (14/12/2023) the ASA list hides unofficial servers that are not hosted by Nitrado until you enable the checkbox Show Player Servers and refresh the session list. Our maps run on our own machine, so they count as player servers. The list can also break for a while after a patch (after 32.21 in December 2023, modded servers vanished from it for about a day), a server on a different version shows brown with no Join button, and a map that is still starting is not listed yet.
ASE. The in-game list is slow and often incomplete. The session and map filters hide servers, a branch or version mismatch hides them (see the guide ASE: cannot join after a game update), and a server that has just started can take a few minutes to appear.
"App ID invalid" is a Steam client bug, not a server fault: Steam fails to hand the connection over to the game when you press Connect in its Servers window or open a steam://connect link.
Check first: the server card on the Servers page. A red Offline dot means the map is down and the admins already see it; a version highlighted as different from the other maps means that map is waiting for its update. If every card shows a newer version than your game, update your game.
preaquatica branch, like our ASE maps.An admin can check that the map is running, that it is on the right build (for ASE: the pinned pre-Aquatica build) and that the server list can see it from outside; after an update the map is restarted and given a few minutes to register again. Ask when the card shows the map online with your version and you still cannot find or join it after a few minutes.
Tell an admin the map, the time (the clock in your profile menu shows the server's time), your character's name, what you carried or had uploaded, and the exact message on the screen. For a transfer: both maps and both times. Report the same day — the backups reach back only about two days. Contact admin is in your profile menu; the Guides page has a question box.