A client of ours has a site that uses PayPal integration. For the past month, all PayPal transactions have come back with status "Payment Failed" despite customers successfully having funds removed on the PayPal side. The setup of the payment gateway is Kentico standard (/CMSModules/Ecommerce/CMSPages/PayPalIPN.aspx for the IPN listener) and nothing odd is popping up in the Kentico event log. The only oddness is that there is absolutely no history in the IPN log on PayPal.

Has anyone else been running into issues like this recently? I'm wondering if PayPal's protocols have changed recently, but I have not been able to find anything.