Permission denied for Rest api call

[ipragmatech]

I have created a paypal, developer and sandbox account. Generated token with the following endpoint

https://api.sandbox.paypal.com/v1/oauth2/token?grant_type=client_credentials

response:

{
"scope": "https://uri.paypal.com/services/subscriptions https://api.paypal.com/v1/payments/.* https://api.paypal.com/v1/vault/credit-card https://uri.paypal.com/services/applications/webhooks openid https://uri.paypal.com/payments/payouts https://api.paypal.com/v1/vault/credit-card/.*",
"nonce": "2017-10-14T10:14:13ZRrNLl-vpeyiZ3XDR-dDKZKg2ezKsG8wy8E3exOOzdbk",
"access_token": "A21AAG6ijXDu1mkpWKlnPNfC_YwDwXm-a9yNsn7_YpQIYmen5NO8fTtFxUmD-S4M2BK5sdaStvu8O_ZOCaq0gs3lQNqDScUwg",
"token_type": "Bearer",
"app_id": "APP-80W284485P519543T",
"expires_in": 32400
}

But got the following issue for the given endpoint:

https://api.sandbox.paypal.com/v1/payments/payment/PAY-6KK93612DG144664xxxxxx

{
    "name": "PERMISSION_DENIED",
    "message": "No permission for the requested operation",
    "information_link": "https://developer.paypal.com/docs/api/payments/#errors",
    "debug_id": "43464f3481061"
}