Hello.

Trying to test refunds on sandbox, but keep on getting "An error occurred during processing. Please try again." error. Charges are created successfully.

Here's the request example:

<?xml version="1.0" encoding="UTF-8"?>
<createCustomerProfileTransactionRequest xmlns="AnetApi/xml/v1/schema/AnetApiSchema.xsd">
   <merchantAuthentication>
      <name>***</name>
      <transactionKey>***</transactionKey>
   </merchantAuthentication>
   <transaction>
      <profileTransRefund>
         <amount>12.34</amount>
         <customerProfileId>1200003458</customerProfileId>
         <customerPaymentProfileId>1200002531</customerPaymentProfileId>
         <transId>20000040807</transId>
      </profileTransRefund>
   </transaction>
</createCustomerProfileTransactionRequest>

Any ideas? Looks like a common problem to me, but I wasn't able to find the solution via search.