If you receive an email from PayPal like this:
That's probably a leftover setting in your PayPal account from some other ecommerce solution you were using before E-junkie. PayPal would only try to notify that URL for payments you receive that didn't involve E-junkie, as we always send our own IPN requirements to PayPal for every checkout; however, repeated failures in such notifications can result in PayPal completely disabling IPN for your account, which would block our ability to process orders for you, so here's how you can fix that:
Log into your PayPal account and go to Profile > More Options > My Selling Tools > Instant Payment Notifications > Choose IPN Settings, where you should choose to Receive IPN Messages (Enabled) and enter this Notification URL (replacing your current Notification URL there that's failing):
That URL is normally used for our eBay integration and will accept any IPNs sent to it regardless of whether the payment involved E-junkie or not, but it will quietly ignore any IPNs it receives for orders it does not recognize.