Some maps in OC need some Valve Source games installed to run properly. Once the mounter starts, stop it. It sucks. Instead, download these files while the game is installing: mega.nz/#F!JPw0laaK!GpEZxImgPlFtktK330N64g These are extracted into your Source SDK Base 2007 install folder.
IP: 173.17.64.218:27031 Password: the usual In the in-game server browser, uncheck "Show map list" at the bottom left and refresh the list to find the server.
I recommend closing the mounter when it starts (after the mod is extracted) and using the Mega link above to mount the games instead. If you want to use the mounting program, keep in mind that it barely works and only mounts games you have already installed on Steam. You will need to have installed and launched Half-Life 2 at least once for the mounting program to mount HL2 correctly. You can also mount Episodes 1 and 2, HL1 Source, Lost Coast, Counter-Strike: Source, and Day of Defeat: Source in case some of the custom maps use assets from those games. These games probably aren't required, but don't complain if you get kicked for not having the maps.