Hello,
I switched to using the regular Subscribe2 widget. and I am having the same issue.
I enter my email address to subscribe. I get the email confirmation. click on the link to confirm, and I am taken to the WP page I created and it asks for my email again. which just sends me another confirmation email in a never ending loop.
Yes, the shortcode is on the WP page I created.
I appreciate your help with this.