Customers have contacted me to let me know that they're unable to complete their orders using PayPal and the Vortx One Page Checkout.
The Vortx OPC was installed on my site [v8102] in October 2010. Customers are telling me that they click the PayPal payment button in Shoppingcart.aspx, sign in/process their payment in PayPal, and are then returned to the Secure Checkout page. However, the OPC wants them to enter a credit card before allowing them to submit their orders. Since they've already 'paid' in PayPal, they abandon the shopping cart! I reproduced the problem myself.
Is this a problem with Paypal or the Vortx OPC? Either way, how can I get this fixed?
Closing: Turned out PayPal Express was not enabled on the Site Configuration Wizard.