Fatal error: Uncaught Error: Class "Vonage\Client\Credentials\Handler\AbstractHandler" not found in /home/qrapp/public_html/vendor/vonage/client-core/src/Client/Credentials/Handler/SignatureBodyFormHandler.php:11 Stack trace: #0 {main} thrown in /home/qrapp/public_html/vendor/vonage/client-core/src/Client/Credentials/Handler/SignatureBodyFormHandler.php on line 11