Проблемы с PayPal – ReturnURL и CancelURL is invalid

[miniShop2] Payment error while request. Request: Array
(
    [METHOD] => SetExpressCheckout
    [PAYMENTREQUEST_0_CURRENCYCODE] => RUB
    [PAYMENTREQUEST_0_ITEMAMT] => 4000
    [PAYMENTREQUEST_0_SHIPPINGAMT] => 0
    [PAYMENTREQUEST_0_AMT] => 4000
    [RETURNURL] => /assets/components/minishop2/payment/paypal.php?action=success
    [CANCELURL] => /assets/components/minishop2/payment/paypal.php?action=cancel
    [PAYMENTREQUEST_0_INVNUM] => 16226
    [L_PAYMENTREQUEST_0_NAME0] => Генератор 10317730 105A Pontiac Aztek 2002 3.4
    [L_PAYMENTREQUEST_0_AMT0] => 4000
    [L_PAYMENTREQUEST_0_QTY0] => 1
)

, response: Array
(
    [TIMESTAMP] => 2019-12-24T07:03:35Z
    [CORRELATIONID] => 8209cd6ad827d
    [ACK] => Failure
    [VERSION] => 74.0
    [BUILD] => 53957121
    [L_ERRORCODE0] => 10471
    [L_ERRORCODE1] => 10472
    [L_SHORTMESSAGE0] => Transaction refused because of an invalid argument. See additional error messages for details.
    [L_SHORTMESSAGE1] => Transaction refused because of an invalid argument. See additional error messages for details.
    [L_LONGMESSAGE0] => ReturnURL is invalid.
    [L_LONGMESSAGE1] => CancelURL is invalid.
    [L_SEVERITYCODE0] => Error
    [L_SEVERITYCODE1] => Error
)