Got 403 response code on payout api calling

[sdpllc]

I am integrating payout through php sdk for codeigniter.
but getting this error when i call api and also i am not sure this will work for live mode as well, i am currently checking for sandbox mode

Error: Got Http response code 403 when accessing https://api.sandbox.paypal.com/v1/payments/payouts?sync_mode=true

this is the url for api calling

http://localhost/kapil/conexcion_web/conexcion/api/WithdrawAmountPaypal