There was an issue earlier that would not always list newly published rooms, you should now be able to create a room, publish it, and others should see that newly published room within a few seconds show up in the server browser. If this does not happen, you can try changing regions from one back to the other, entering then leaving the credits or training, or simply hitting the "Refresh" button a few times.
Quick Patch for April 26th
Source: Steam Community (opens in a new tab)
Build and release context
Steam update times within 24 hours of this post. Matching dates do not confirm which build it describes.
Build 6599202 · public branch
Steam updated · First observed
Recorded Steam release date:
Within one calendar day of this post (UTC). The listed date does not establish an exact launch time.