The offline transaction has not completed online verification. At this time, the refund will respond to this json.
{
"code": "processing_error",
"message": "Unknown failure reason FAIL.",
"requestId": "07096b86-d70a-4df3-99ca-8acd61f26b6a",
"requestType": "REFUND",
"type": "api_error"
}
Although after the connection is restored, the refund can be normal after the transaction verification is completed.