I got this message from PayPal recently about a site that I use for a site that includes an Expresso Store.
Please check your server that handles PayPal Instant Payment Notifications (IPN). Instant Payment Notifications sent to the following URL(s) are failing: /en/?ACT=31&H=48849e7094c749963e181a1e04b13b16 If you do not recognize this URL, you may be using a service provider that is using IPN on your behalf. Please contact your service provider with the above information. If this problem continues, IPNs may be disabled for your account. Thank you for your prompt attention to this issue.
and Store has stopped registering my PayPal payments (it lists them as pending after they have been paid). Do you know if this is a Store problem, or has PayPal changed the way it deos IPNs? I did not change anything myself.
EE 2.5.3 Store 1.6
Good idea with support on EE Stackexchange by the way!