Minishop - PayPal - Certificate issuer is not recognized

Кто знает что за сертификат требует PayPal?

[2020-10-06 09:50:40] (ERROR @ *****/core/components/minishop2/custom/payment/paypal.class.php : 85) [miniShop2] Payment error while request. Request: Array
(
    [METHOD] => SetExpressCheckout
    [PAYMENTREQUEST_0_CURRENCYCODE] => EUR
    [PAYMENTREQUEST_0_ITEMAMT] => 35
    [PAYMENTREQUEST_0_SHIPPINGAMT] => 10
    [PAYMENTREQUEST_0_AMT] => 45
    [RETURNURL] => https://******/*****/assets/components/minishop2/payment/paypal.php?action=success
    [CANCELURL] => https://******/*****/assets/components/minishop2/payment/paypal.php?action=cancel
    [PAYMENTREQUEST_0_INVNUM] => 519
    [L_PAYMENTREQUEST_0_NAME0] => Poster «The Exploited. Punks Not Dead»
    [L_PAYMENTREQUEST_0_AMT0] => 35
    [L_PAYMENTREQUEST_0_QTY0] => 1
)
, response: Peer's Certificate issuer is not recognized.

response: Peer's Certificate issuer is not recognized — что это может означать?