Fatal error: Uncaught Error: Interface "PayPal\Handler\IPayPalHandler" not found in C:\xampp\htdocs\wp-content\plugins\nextgen-gallery-pro\modules\paypal_checkout\vendor\paypal\rest-api-sdk-php\lib\PayPal\Handler\OauthHandler.php:18 Stack trace: #0 {main} thrown in C:\xampp\htdocs\wp-content\plugins\nextgen-gallery-pro\modules\paypal_checkout\vendor\paypal\rest-api-sdk-php\lib\PayPal\Handler\OauthHandler.php on line 18