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

)
[401] Error connecting to the API (https://api.cybersource.com/tms/v1/instrumentidentifiers/7020000000000137654/paymentinstruments?offset=0&limit=20)