I had a problem where it wouldn't let me sign in. It would send me to yuku and the sign-in there would still fail and I'd go days without being able to post until a sign-in would succeed.
I have found a solution though I have no idea why it works. When I can't sign in here, I go over to the Talking Xena board. There, I am able to sign in right away. Then, since they are both yuku boards, I come back here and am already signed in.