Make sure that you have accepted the "PayPal Payments Pro" agreement in your PayPal account after you have been approved by PayPal for PayPal Payments Pro. If you have accepted their agreement but are still getting this error, PayPal also occasionally acknowledges the agreement and activates Virtual Terminal but somehow misses activating PayPal Payments Pro itself; if your PayPal "Get Started" summary screen only shows Virtual Terminal and nothing about PayPal Payments Pro, please contact PayPal support to get your PayPal Payments Pro service activated.
If you are only using PayPal Payments Standard with a regular PayPal personal, Business or Premier account (i.e., if you have not upgraded to PayPal Payments Pro), please go to Seller Admin > Payment Preferences and make sure you have PayPal Payments Standard checked (rather than PayPal Payments Pro) and click Submit to save any changes you make.
