subscribe2 – no confirmation email sent

I’m using Subscribe2 2.2.4 and I’m on wordpress 2.0.2
My site is hosted by Yahoo.

At one point I had the plugin working, i believe I was on 2.2.0 and then I upgraded to 2.2.4 and now, new subscribers to my post are not getting the confirmation emails when they get the submit button to subscribe.
Has anyone else noticed this problem? Is there a known solution to this problem or perhaps I missed a setup set?

Thanks in advance