Fatal error: Uncaught Error: Class "GuzzleHttp\Promise\RejectionException" not found in C:\xampp\htdocs\slip\laravel-webhooks\vendor\guzzlehttp\promises\src\CancellationException.php:10 Stack trace: #0 {main} thrown in C:\xampp\htdocs\slip\laravel-webhooks\vendor\guzzlehttp\promises\src\CancellationException.php on line 10