Laravel 5.4 S3 Bucket Image Upload Issue

I get below issue while upload file using s3 bucket.

(1/1) InvalidArgumentException
Missing required client configuration options: 

My S3 Array in config/filesystems.php file

's3' => [
            'driver' => 's3',
            'key' => env("S3_KEY",'mykey'),
            'secret' => env("S3_SECRET",'my_secret'),
            'region' => env("S3_REGION",'my_region'),
            'bucket' => env("S3_BUCKET",'my_bucket')
        ],  

I think issue is in Above s3 array. please let me correct.