[Plugin: AutoChimp] Auto Chimp not syncing with Mail Chimp

I have gotten a ton of sign-ups on my site with Auto Chimp but none of them are being sent to Mail Chimp. I have my API key on the options page and I’ve checked it for accuracy. I get a notification from Word Press that I have a new sign-up but they are not on my mailing list.

http://wordpress.org/extend/plugins/autochimp/