Can't process refund, was told is a Prestashop aspect to address

[egzibeo]

I cannot process a partial refund (I didn't have to process a full refund yet), I get error in the backend of prestashop- "an error ocurred during this refund - user authentication failed". I use PayPal Pro as payment gateway, I spoke with PayPal, all credentials are fine at their end, when attempting to process a refund their system doesn't receive any request. I was told that "Kindly contact Prestashop to determine how the refund API works within Prestashop. If customers are able to make payment to your website, but when attempting to refund, it gives you this error, it means it is running on two separate API and two separate credentials." Can you help me in any way to understand why I can't process a refund?

 

Thank you,

 

Cris