Hey there -
Sometime last spring I moved from Dreamhost to another provider, in which I did a clean install of WordPress on the new provider and reconnected my Jetpack account to WordPress.com. Everything seems to be working peachy keen EXCEPT Jetpack Subscriptions and Jetpack Contact form. I could not find explicit documentation on configuring the backend (such as php mail or sendmail), but we have verified that php mail/sendmail IS working with another contact form (which is currently installed) or any of my domain generated emails like password resets/new user accounts and the like.
For the Jetpac Subscriptions, if someone adds their email address, there is no confirmation page nor is a confirmation email sent. I've had myself and others test this and it's the same for everyone. Help?