On Pro Edition 2, the email sends through your iPad's Mail app, which is managed by iOS.
Make sure email is set up on your iPad. To change which email address your iPad is set on, go into the iPad Settings > Mail, Contacts, Calendars > Select the mail account or add a new one from here.
Similarly to our apps, the Mail app will queue your emails in the Outbox folder if you're not on a reliable internet connection. After they send, they are moved to the Sent folder. Check your outbox in the Mail app to see the status of your emails.