Hi @DarrenDev
Thank you for posting to the PayPal Community.
I looked at the transaction ids that you are not able to refund, and the payee email associated with the transactions is not added or confirmed to any Sandbox PayPal Account. If you log into the buyer account, you will see that the payment is currently in an unclaimed status.
If you add and confirm the email in one of the seller accounts that is on boarded to your app, once the payment is completed, you will be able to refund the payment.
Thank you,
Jennifer
MTS
PayPal
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