The following exception may occur if you have insufficient privileges for the bucket and prefix you're trying to access:
S3_SPOOLDIR_20 - Cannot connect to Amazon S3, reason : com.amazonaws.services.s3.model.AmazonS3Exception: Access Denied (Service: Amazon S3; Status Code: 403; Error Code: AccessDenied; Request ID: 5D46A336DE688820), S3 Extended Request ID: 8TZSsnvthDUp+DmFxxHJSBZwn84ubYnY8Y1s5lD4LFiyTPhK6ZPye57hPxg5WxSYOarqBr79IW8=
Ensure you have s3:ListBucket and/or s3:ListAllMyBuckets privileges.