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

)
[401] Error connecting to the API (https://api.cybersource.com/sfs/v1/file-details?startDate=2019-09-20&endDate=2019-09-30&organizationId=testrest)