Fatal error: Uncaught Error: Class "Aws\Crypto\MaterialsProvider" not found in C:\WebServer\htdocs\bookshelf\vendor\aws\aws-sdk-php\src\Crypto\KmsMaterialsProvider.php:16 Stack trace: #0 {main} thrown in C:\WebServer\htdocs\bookshelf\vendor\aws\aws-sdk-php\src\Crypto\KmsMaterialsProvider.php on line 16