Fatal error: Uncaught Error: Class "Core\Authentication\CoreAuth" not found in C:\xampp\htdocs\www\zdxnew\web\vendor\paypal\paypal-server-sdk\src\Authentication\ClientCredentialsAuthManager.php:29 Stack trace: #0 {main} thrown in C:\xampp\htdocs\www\zdxnew\web\vendor\paypal\paypal-server-sdk\src\Authentication\ClientCredentialsAuthManager.php on line 29