GetPurchaseAndRefundDetails Samplecode is Running.. 
stdClass Object
(
    [response] => stdClass Object
        (
            [rmsg] => Authentication Failed
        )

)
[401] Error connecting to the API (https://api.cybersource.com/reporting/v3/purchase-refund-details?startTime=2019-02-01T12%3A00%3A00-05%3A00&endTime=2019-02-20T12%3A00%3A00-05%3A00&paymentSubtype=ALL&viewBy=requestDate&limit=2000)