s3 connection issue

[Ardhendu100]

'dir' => ['storage'],

'disks' => [
    's3' => [
        'driver' => 's3',
        'key' => env('AWS_ACCESS_KEY_ID'),
        'secret' => env('AWS_SECRET_ACCESS_KEY'),
        'region' => env('AWS_DEFAULT_REGION'),
        'bucket' => env('AWS_BUCKET'),
        'alias' => 'S3 Storage',
        'URL' => env('AWS_URL', null),
    ],
],


'route' => [
    'prefix' => 'elfinder',
    'middleware' => ['web', 'auth'], // Set to null to disable middleware filter
],

'access' => 'Barryvdh\Elfinder\Elfinder::checkAccess',
'roots' => [
    [
        'driver' => 'Flysystem',
        'path' => '/',
        'URL' => env('AWS_URL', null),
        'filesystem' => 's3',
        'alias' => 'S3 Storage',
        'uploadAllow' => ['image'],
        'uploadDeny' => ['all'],
        'uploadOrder' => ['deny', 'allow'],
        'accessControl' => 'Barryvdh\Elfinder\Elfinder::checkAccess',
    ],
],

`
this is config/elfinder.php , I am getting error "Invalid backend configuration.
Readable volumes not available."