return url doesn't return transaction details

[rambohouse]

HI,

 iam not able to getting return transaction details in my function. it says 

{"name":"NOT_AUTHORIZED","details":[{"issue":"PERMISSION_DENIED","description":"You do not have permission to access or perform operations on this resource."}],"message":"Authorization failed due to insufficient permissions.","debug_id":"369663b2b775a","links":[{"href":"https://developer.paypal.com/docs/api/orders/v2/#error-PERMISSION_DENIED","rel":"information_link"}]}