Windows Admin Center Login

I have done a fresh install of Windows Admin Center 2007 several times and each time I click on the URL provided after install and cannot log in. It just prompts a log in screen and nothing that I try works and I wasn't able to find the default login for WAC. I've tried several times using a self signed cert and a cert that is signed by a trusted CA. How am i supposed to log into WAC when it's first installed??