Fatal error: Uncaught Error: Class "Vonage\Client\Credentials\Handler\AbstractHandler" not found in /var/www/html/core/vendor/vonage/client-core/src/Client/Credentials/Handler/SignatureBodyHandler.php:10 Stack trace: #0 {main} thrown in /var/www/html/core/vendor/vonage/client-core/src/Client/Credentials/Handler/SignatureBodyHandler.php on line 10