ARK: Survival Evolved server status checker
Survival Evolved separates the port players connect through from the port that answers queries, and forgetting the second one is the classic reason a working server never appears in the browser.
Which ports a ARK: Survival Evolved server needs
Both are UDP and they are different numbers. This tool needs the query port, not the game port. Older ARK guides also mention a third raw-socket port; whether you need it depends on your setup, but the query port is the one that decides whether anything can see your server.
If it still shows offline
If the query port is open and the check still times out, wait longer. ARK loads its entire save before it starts answering queries, and a large map with a lot of built structures can take several minutes. Checking straight after a restart reports offline for a server that is simply still starting.