Hello,
Thank you for posting to the PayPal Sandbox Community.
I tested the IPN Simulator in Sandbox using https://webhook.site it is a website that you can use for IPN and Webhook simulation.
IPNs are being sent with no issues.
Here is the information on implementing a listener: https://developer.paypal.com/docs/ipn/integration-guide/IPNImplementation/
Your listener must send the post back in an https request.
Here is the information on IPN Architecture:
https://developer.paypal.com/docs/ipn/integration-guide/IPNIntro/#ipn-protocol-and-architecture
Here is a basic troubleshooting guide to receiving 404 errors with the IPN Listener:
https://www.paypal.com/lu/smarthelp/article/how-do-i-troubleshoot-instant-payment-notification-(ipn)-ts2082
Thank you,
Jennifer
PayPal
... View more