I received a 'PayPal Instant Notification Warning' email from PayPal. What should I do now?

Each IPN message sent from PayPal has to be acknowledged by Chargebee.

If PayPal doesn't receive this acknowledgement, it treats the IPN as a failure and sends this email.

Please check if you have configured the PayPal IPN as per instructions here and reach out to support with details, for further assistance.