Fatal error: Uncaught Error: Class 'Vonage\Client\Credentials\Handler\AbstractHandler' not found in C:\xampp\htdocs\kit\vendor\vonage\client-core\src\Client\Credentials\Handler\SignatureQueryHandler.php:10 Stack trace: #0 {main} thrown in C:\xampp\htdocs\kit\vendor\vonage\client-core\src\Client\Credentials\Handler\SignatureQueryHandler.php on line 10