I assume you saw it on the LAN list from the same computer that is running the server. It sounds like the server is running fine. If you have another computer on your network running ARK, it should also see it on the LAN list (OK, I am doing a bit of assuming since I have never run an ARK server, but I assume it behaves in the usual way). If not, then you might have a firewall (windows firewall?) running on the computer with the server and it is stopping the connection. You might find more information about that here:
https://ark.gamepedia.com/Dedicated_Server_Setup#Windows_.28Firewall_and_Allow_Rules.29
If you are seeing it on the LAN list on another computer on your network, but not on the ARK server list, then it is likely something is wrong with your port forwarding ... in that case, tell us more about your setup, including model numbers of all the routers and/or modems you have, WiFi or Ethernet, etc.