How do I make my server appears on the unofficial list?
is should appear outomatically. but Unofficial list si so long, it does not show all servers. use the link from your server to access your game, and if u your friends struggle to see the server, let them join via your friend-steam page
This was answered on the FAQ:
But to build on that: The ARK Server system queries all the ARK servers that are out there and active. It then builds the list of all the servers. Due to the way the system times out, it gets to a point and just stops.
Whether or not your server is on that list, is totally dependent upon random luck and chance.