Transitioning from PayPal’s sandbox to your live site, there are certain settings you must configure on PayPal in order to process transactions; failing to do so will result in the following errors: 

Error: 10548 The merchant account is unable to process transactions: PayPal requires all of its merchants to possess business accounts. You can sign up for one by clicking the Sign Up option on the top right of the screen and choosing Business Account.



Error: 10501 This transaction cannot be processed due to an invalid merchant configuration: Signing the billing agreement present on the overview page will automatically sign you up for Website Payments Pro, which will allow you to accept payments. 

Error: 10575 The API operation is not allowed/11452 Merchant not enabled for reference transactions: Enabling reference transactions on your PayPal account allows Chargebee to communicate with it and automate payments for subscriptions. While reference transactions are automatically enabled in the sandbox, you need to contact PayPal to enable reference transactions on your live site. It is a simple procedure that is accomplished on the back end.