roommate and I can't join same game

Hi guys, hope it's okay to ask about tech issues here.

My roommate and I both just got AOE3 on steam. When we logged into multiplayer we were both able to join some (but not all) games being hosted by others and have players join our games, but we were unable to connect to each others' games or join the same game hosted by an outside party. I googled for awhile last night and tried following the steps of this video but unfortunately I'm not very tech savvy and could not get it to work. Any advice would be appreciated.