We want you to be able to play our game, so please read this post.
Posted by [ladnet]brad on Aug 15th, 2012
We’re sure you noticed it already, but the Steam server browser doesn’t list any Action Half-Life 2 games for some time now. Unfortunately that’s not our fault, all third party Source engine mods are affected (thanks Valve, you did it again). For the time being please refer to this list of servers if you want to play. In case you are a server admin and want your server to be added to this list, just use the comments for this post.
TP W/O ROUNDS: 184.108.40.206:27018
By the way: behind the scenes work on the next version continues. We just don’t have any news to share at the moment.
UPDATE: SolidSnake27 posted a link to a news post by the No More Room in Hell team. We were able to verify their solution: just add the line "sv_master_legacy_mode 0" to your server.cfg (without the "" of course), restart your server and it will show up in the server browser again. You do not need to issue the heartbeat command that's mentioned in the news post, AHL2 code already does this for you.