Intermittent lost PayPal payment notifications
Q: When my clients pay with PayPal, it usually works, but occasionally iPanel does not record a payment. Why is this, and how do I fix this?
PayPal has been having significant problems with its IPN system this year (as noted by PayPal itself and many of its users in the PayPal Live Site Status and PayPal Developer Forums at paypaldeveloper.com) and the result has been that IPN notifications will occasionally not be sent by PayPal.
Since those notifications are not sent by PayPal, there is of course no way for iPanel to receive them, and thus iPanel never credits your clients' accounts for the payment (nor provisions the hosting accounts they ordered).
In the May, 2008 issue of their DevTalk newsletter, PayPal recommended that instead of relying solely on IPN, developers should also add support to their products for periodically polling PayPal's servers and checking for missed payments as a workaround. While an arguably better solution would be for PayPal to fix the IPN system, this workaround does indeed provide a clumsy but effective way to ensure that payments are never missed.
As of iPanel v3.6.20, this option is now available. In order to use it, you must enable API access on your PayPal account (click here for instructions). This will provide you an API username, password, and signature, which you must setup in iPanel by clicking Configuration, Configure payment gateways, and filling out the fields under the "PayPal" section.
Once you've configured these items, iPanel will periodically (once every four hours) poll PayPal's servers, check for missed payments, and credit your users' accounts as needed.
IMPORTANT: This article only applies to you if you are only missing some (not all) of your PayPal payments in iPanel. If you are not receiving notification of any of your payments, it's likely that IPN is simply turned off in your PayPal account, or that you've got multiple addresses on your PayPal account (click here for details).