QUOTE (vertical1 @ Oct 26 2009, 08:53 AM)

PayPal's site is listing it as an API error, and since I've never had this issue before in the last three years, I'm gonna assume it's a software issue on the NS side until someone tells me otherwise.
Any decline comes over as an "API Error" with an Error Code, it's how the information in a decline is transmitted.
Did you look at the corrective action listed in the API link? "Instruct the customer that PayPal is unable to process the payment and redisplay alternative payment methods with which the customer can pay."
Assuming is never a good thing, it'll frustrate you and your customers, at this point you're going to wait for NS to say "It's not our issue" instead of going to PayPal in the meantime to get further information. You also specified that it's "a few" transactions, to me if the API was transmitting invalid information it would affect "every" order processed via PayPal.