This post will discuss how to debug IPN issues that may come up between Paid Memberships Pro and PayPal.

IPN stands for “Instant Payment Notification” and it is used by PayPal Express, PayPal Standard, and PayPal Website Payments Pro to send information about PayPal orders and subscriptions to your website. (Payflow Pro does NOT use IPN. If you are using Payflow, make sure you are also using the Payflow Pro recurring orders addon.)