I've installed the plugin but can't seem to get the submit button to work. It definitely tries to add it to the list, but nothing happens besides the page refreshes with what appears to be some additional code in the URL.
I've tried using the Contact Form 7 with the Constant Contact add on. No luck there either.
Any help with this would be great, I'm currently using the WP-Mail-SMTP to fix a couple outgoing email issues I was having. Any way that is interfering with this API?