Intuit PaymentNetwork will be discontinued on 5/31/2016.
Learn more about the transistion.
This article includes the step-by-step procedures for turning on or moving the IPN payment links on customized invoices.
NOTE: QuickBooks 2015 and Enterprise v.15 do not have this option. A future release will add the ability back to Invoices.
Turn on the IPN link on customized invoice templates
Move the IPN link on the customized invoice templates
If these steps do not resolve the issue, you can read discussions and post messages and questions relating to your issue on the Intuit QuickBooks Community site for free or you can contact a technical support agent for additional guidance. Fees may apply.