Question about LAN on EE

Trying to play lan with a roommate on Steam's AOM: EE. Only got one copy of the game so he logs on one account and goes offline. I go online with the same account. I host a LAN and when they try to join, they are never able to connect. I've tried various combinations. Both of us offline, one off one on. One person makes the room, the other joins. Vice-versa.

I've tried looking around (googling) for answers but there isn't much to go on anyways. Does anyone have any suggestions or tips? Outside of buying a second copy of the game (and who knows, maybe it still won't work). Thanks in advance!