Merge pull request #247011 from gmndrg/main

Updated with a common error with invalid doc key

Author: prmerger-automator[bot]

articles/search/cognitive-search-common-errors-warnings.md

@@ -9,7 +9,7 @@ ms.author: heidist
 ms.service: cognitive-search
 ms.custom: ignite-2022
 ms.topic: conceptual
-ms.date: 07/19/2023
+ms.date: 08/01/2023
 ---
 
 # Troubleshooting common indexer errors and warnings in Azure Cognitive Search
@@ -71,6 +71,7 @@ Indexer read the document from the data source, but there was an issue convertin
 | Reason | Details/Example | Resolution |
 | --- | --- | --- |
 | The document key is missing | `Document key cannot be missing or empty` | Ensure all documents have valid document keys. The document key is determined by setting the 'key' property as part of the [index definition](/rest/api/searchservice/create-index#request-body). Indexers emit this error when the property flagged as the 'key' can't be found on a particular document. |
+| The document key is invalid | `Invalid document key. Keys can only contain letters, digits, underscore (_), dash (-), or equal sign (=). ` | Ensure all documents have valid document keys. Review [Indexing Blob Storage](search-howto-indexing-azure-blob-storage.md) for more details. If you are using the blob indexer, and your document key is the `metadata_storage_path` field, make sure that the indexer defintion has a [base64Encode mapping function](search-indexer-field-mappings.md?tabs=rest#base64encode-function) with `parameters` equal to `null`, instead of the path in plain text. |
 | The document key is invalid | `Document key cannot be longer than 1024 characters` | Modify the document key to meet the validation requirements. |
 | Could not apply field mapping to a field | `Could not apply mapping function 'functionName' to field 'fieldName'. Array cannot be null. Parameter name: bytes` | Double check the [field mappings](search-indexer-field-mappings.md) defined on the indexer, and compare with the data of the specified field of the failed document. It may be necessary to modify the field mappings or the document data. |
 | Could not read field value | `Could not read the value of column 'fieldName' at index 'fieldIndex'. A transport-level error has occurred when receiving results from the server. (provider: TCP Provider, error: 0 - An existing connection was forcibly closed by the remote host.)` | These errors are typically due to unexpected connectivity issues with the data source's underlying service. Try running the document through your indexer again later. |