PayPal has posted a system status alert confirming some IPNs may be delayed. We depend on IPN to receive order data back from PayPal and confirm completed payment, so any IPN delays would affect how quickly we can notify you of a sale, log the transaction, send thank-you emails, and issue download links or purchased PIN/key/license codes.
You can reassure concerned buyers that their download link or any codes they'd purchased will be sent as soon as PayPal catches up with their delay.
You may also choose to satisfy impatient buyers manually by using your Seller Admin > "Send free download link / code". In that case, you can also prevent an additional link/code from being issued to them when the IPN finally arrives, by entering your Transaction ID for their payment (which you can find in your PayPal account history or receipt email) in your Seller Admin > Block Transactions screen.
Update 1: Delay in receiving IPNs - Jul 26
Posted by PayPal_Updates on Jul 26, 2011 7:23:19 PM
UPDATE 1: We are continuing to work towards resolving this issue. We will provide the next update by Jul 26, 9:00 PM PDT (Jul 27, 4:00 AM GMT) or sooner if there's a status change.
Sent Jul 26, 7:21 PM PDT by ASR
NOTIFICATION: We are experiencing a system issue affecting Instant Payment Notifications. Merchants may currently be experiencing some delays in receiving IPNs.
Sent Jul 26, 6:31 PM PDT by ASR
Start time: Jul 26, 6:05 PM PDT (Jul 27, 1:05 AM GMT)
Estimated time for resolution: TBD
At this time, there is no alternative work-around.