TRANSACTION_REFUSED response in sandbox while following Reference Transaction Integrations steps

[chichab]

I am following this link: https://developer.paypal.com/docs/limited-release/reference-transactions/#use-a-reference-transactio...

But the request I created is being refused.

{

    "name": "TRANSACTION_REFUSED",

    "message": "The request was refused",

    "information_link": "https://developer.paypal.com/docs/api/payments/#errors",

    "debug_id": "2c9d80b1256ae",

    "code": "TRANSACTION_REFUSED"

}

I'd like to get more information on the error