I am using PayPal Advanced. I ran tests on it about one month ago and it was working fine. Then I started getting "pending payment" in my magento admin panel even though the payment had gone through. Last Saturday, a customer reported that it froze during the checkout process so she wanted to confirm if her payment went through. It did go through. Then I ran a real test transaction using the company credit card. Now all purchases say "Payment has been declined. Please try again" and Magento cancelled the payments. BUT the payment went through properly on PayPal. I spoke to PayPal, they adjusted some setting in PayPal Manager and on Paypal.com. I set up my IPN as well.
Now payments properly appear as "processing" in my admin panel and payment successfully goes through PayPal. BUT "Payment has been declined. Please try again" still appears whenever a customer tries to checkout. From the backend, I have no way of knowing that the customer received this message. I set the payments to "authorize" not "sale" so I can void duplicate transactions — every time a customer puts their credit card information in again, it charges them again. PayPal says it is due to an extension I am using… I find this hard to believe since it worked fine with all of my extensions before and then randomly stopped working.
I upgraded to Magento 1.9. All extensions work properly. AFTER UPGRADING, I started using PayPal advanced. So it did not tell customers payment is declined on Magento 1.9 with all extensions, and now it does.
Best Answer
I found the solution to the problem. I am using magento 1.7.0.2.
IN PAYPAL UNDER Profile>My Selling Tools>Instant Payment Notifications Click Update MAKE SURE TURN OFF IPN IS selected. IPN will be disabled.
Notification URL: https://www.yourshoppingcart.com/shoppingcart/paypal/ipn/
This is, because Magento overrides the Standard Paypal IPN and sends another from himself.