I've setup and configured an event to require paid registration via Paypal in the DNN Events 6.2.1 module.  My DNN installation is version 7.3.2.  Currently I am testing the payment processing using the sandbox site with test Paypal accounts I created.  The function appears to work properly to the end user, so that when they register for the event they are taken to paypal, where they can complete payment and then they are returned to the DNN Events module which displays a confirmation message.  However, the concern is that the Paypal payment details are not relayed to the Events module at all (such as the PayPal transaction ID) and the user is automatically registered for the event even if they don't complete the Paypal payment or if their payment did not complete processing.  To configure the Events module to receive Paypal payments, I applied the Paypal merchant account email address and the Paypal URL to the Events module settings, and I applied the merchant's Paypal email address to the configured event's settings.  Are there other settings that need to be set to correspond with the Paypal API.  I know with other store modules I've had to specify the account's API keys and/or specify the return url.  Should I set the Paypal settings in the admin > Site Settings?  Even changing the friendly URL settings in the install's web.config has not helped.  Any details anyone can provide would be greatly appreciated.