I don't see my server in the in-game server list
It is a well-known issue. ARK server shows just a small amount of online servers (almost randomly chosen) in it's listing. So it is just a small chance that your server will appear in that internal game list.

However, there are lots of services across the Web that maintain the lists of online servers (e.g. https://ark-servers.net/) so we would recommend to use one of them to attract more players.