I had tried the same. The records get added, the Thank you page as the right shortcode- [pdb_signup_thanks]. After adding any record, the page spins for a while but never displays any message. So it probably means the shortcode never gets executed. I had tried both session options – php and database. I get the same results meaning no signup email. I bought the pdB Email template plugin from you and I can manually send them welcome e-mails. So the email is working.