Hello Adam- Thank you for your suggestions. I have got this very same issue now. I have been using a different application which handles the IPN messages sent to Notification URL from PayPal and we receive them and process it and send PayPal back 200. Last week we upgraded to new application that don't require any IPN handling so I set disable IPN feature on my PayPal account. But still I received this IPN Notification warning email today. PayPal trying to send IPN data to our old IPN Notification URL and end up with 404 HTTP Response eventually. Should we need to send blank HTTP 200 OK response to Paypal for the url they are trying to hit?
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