Receiving IPN notices, however paypal is not longer receiving my response

[conundrumstudio]

Hi All,

My ipn setup has worked for the past 10 years, nothing has changed, no ips are blocked.  My customer software still receives the paypal IPN notices when a purchase is made.

However, the response I send to PAYPAL (which is a valid paypal ipn response url) is no longer received or processed.  So I get all those IPN warning messages and when for example a customer cancels a subscription, instead of getting one cancel message I get a dozen of them as paypal no longer receives my response messaging saying hey I got it.

Something change in that area that I don't know about?  I use PHP to send the response and it has worked for a very long time.  What detail has changed that would cause this?

Thank you!

[conundrumstudio]

from digging into this, the old code would get the ipn message from paypal, it would then do a notify-validate to check that it came from paypal and process accordingly.  that was it and it has worked for a decade.

all the recent examples I see do one extra step, they send another message after the validate that is a 200 response with an empty message.

Perhaps that is the detail that changed?  Previously just doing the validate was enough to tell paypal that you got it, and now it requires an additional message to let paypal know, hey I definitely got it?

stabbing in the dark as this has worked for so long it hasn't been looked at for ages.