Fatal error: Uncaught Error: Interface "Aws\Crypto\MaterialsProviderInterface" not found in C:\WebServer\htdocs\bookshelf\vendor\aws\aws-sdk-php\src\Crypto\MaterialsProvider.php:4 Stack trace: #0 {main} thrown in C:\WebServer\htdocs\bookshelf\vendor\aws\aws-sdk-php\src\Crypto\MaterialsProvider.php on line 4