Fatal error: Uncaught Error: Class 'Nexmo\Client\Callback\Callback' not found in /home/flexinettek/public_html/vendor/nexmo/client/src/Voice/Message/Callback.php:13 Stack trace: #0 {main} thrown in /home/flexinettek/public_html/vendor/nexmo/client/src/Voice/Message/Callback.php on line 13