ARK: Survival Ascended server status checker
ARK has always used a separate query port, and it is the single most common reason an Ascended server runs fine but never appears in the browser.
Which ports a ARK: Survival Ascended server needs
The port players connect through and the port that answers queries are different numbers, both UDP. The tool needs the query port. Guides written for Survival Evolved often list a third port as well; Ascended's requirements differ from the older game's, so check your own server's configuration rather than assuming a carried-over setup is right.
If it still shows offline
If the query port is open and the query still times out, give the server more time. ARK servers can take several minutes to finish loading a large save, and they do not answer queries until they are fully up — checking too soon after a restart reports offline for a server that is merely still starting.