What is JotForm?
JotForm is a free online form builder which helps you create online forms without writing a single line of code. No sign-up required.
At JotForm, we want to make sure that you’re getting the online form builder help that you need. Our friendly customer support team is available 24/7.
We believe that if one user has a question, there could be more users who may have the same question. This is why many of our support forum threads are public and available to be searched and viewed. If you’d like help immediately, feel free to search for a similar question, or submit your question or concern.
As you can see here: https://developer.paypal.com/docs/classic/api/errorcodes/ the error above refers to the following:
10500 Invalid Configuration This transaction cannot be processed due to an invalid merchant configuration. Occurs when you have not agreed to the billing agreement. DoDirectPayment 10501 Invalid Configuration This transaction cannot be processed due to an invalid merchant configuration. Occurs when the billing agreement is disabled or inactive. DoDirectPayment
You need to agree and active the billing agreement in your PayPal account.
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