Paypal Express payment fails "Request operation failed. error message: Merchant not eenabled for reference transactions I have created a sandbox merchart account, paypal PRO, and configured the Paypal Express plugin and PayPalExpress and PayPalRecurring in my reseller account in PBA 5.5.5. The Test Connection works fine (from PBA: Home>System>Settings>Payments Processing>Payment Method>). From CP and from online store, when I select PayPal express as payment method, and submit the order I receive the error: "Request operation failed. error message: Merchant not eenabled for reference transactions" Any clue on what could it be the problem? Thanks S.