Getting error in Billing Plan and Agreement API: DPRP is disabled for this merchant

[Harish_lsn]

I am getting error "DPRP is disabled for this merchant", i already have enabled Pro feature on my Sandbox account (Please check highlighted account in attached image), i am using Billing Plan and Agreement API (REST API) for creating recurring profile with Credit Card. But always getting this response

Array
(
    [http_code] => 400
    [json] => Array
        (
            [name] => DPRP_DISABLED
            [message] => DPRP is disabled for this merchant.
            [information_link] => https://developer.paypal.com/docs/api/payments.billing-agreements#errors
            [debug_id] => da50f8d657b45
        )

)