Now, for my own issue: I'm having the same issue as @elgguser, same settings and all.  I noticed it first because, when I would register as a user, I would be sent two confirmation e-mails.  I realized this was because, in addition to Site...

@ni3 (and others) If you have the captcha plugin enabled, you need to disable it.  I read that somewhere else around here, and it did the trick for me.  Site Access uses its own captcha. Hope that helps :)