Fatal error: Uncaught Error: Interface 'Nexmo\Entity\JsonSerializableInterface' not found in /var/www/ebeosi.com/vendor/nexmo/client-core/src/Account/Balance.php:13 Stack trace: #0 {main} thrown in /var/www/ebeosi.com/vendor/nexmo/client-core/src/Account/Balance.php on line 13