Nostalrius Begins - Quality wow vanilla realm (1.12)

Just downloaded the game and registered but I can't log in. The realm list is set to "set realm list login.nostalrius.org" but when I log in I get the "your password or username is wrong..." Any idea what could be wrong? Would appreciate a fast response since I wanna get leveling tonight

P.s I have the mac client.

You know that the forum account and the game account are separate? And you definitely created a game account through https://en.nostalrius.org/ (scroll all the way down).