failedDocuments property
A list of documents that were not added to the index because the document failed a validation check. Each document contains an error message that indicates why the document couldn't be added to the index.
If there was an error adding a document to an index the error is reported in your AWS CloudWatch log. For more information, see Monitoring Amazon Kendra with Amazon CloudWatch Logs
Implementation
final List<BatchPutDocumentResponseFailedDocument>? failedDocuments;