> For the complete documentation index, see [llms.txt](https://v2.dataos.info/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://v2.dataos.info/concepts/resources/nilus/troubleshooting.md).

# Troubleshooting

Use this page as the global triage path before opening connector-specific runbooks.

## First Response

1. Identify the pipeline mode: batch, CDC, stream, or metadata.
2. Capture the resource name, tenant, owner, run time, source, destination, and exact error text.
3. Check the latest run status and logs.
4. Confirm whether the failure happened before extraction, during extraction, during load, or after the final metrics push.
5. Compare the current config with the last known-good config.
6. Use connector pages for source- or destination-specific error messages.

## Symptom Map

| Symptom                        | Most likely area                                                   | First document                                                                           |
| ------------------------------ | ------------------------------------------------------------------ | ---------------------------------------------------------------------------------------- |
| Authentication failure         | Credentials, projection, depot, or URI shape.                      | [Secrets and Projections](/concepts/resources/nilus/concepts/secrets-and-projections.md) |
| `Source not supported.`        | Unsupported URI scheme or source mode.                             | [Sources](/concepts/resources/nilus/sources.md)                                          |
| `Sink not supported.`          | Unsupported destination URI or destination mode.                   | [Destinations](/concepts/resources/nilus/destinations.md)                                |
| Table name format error        | `source_table` or `dest_table` not qualified as expected.          | Connector page for the source or destination.                                            |
| Run is slow but succeeds       | Throughput, source paging, load batch size, or destination layout. | [Pipeline Optimization](/concepts/resources/nilus/pipeline-optimization.md)              |
| CDC cannot resume              | Source retention, offsets, or schema history.                      | [Common Errors](/concepts/resources/nilus/troubleshooting/common-errors.md)              |
| Destination row count is wrong | Write strategy, primary key, filters, or incremental cursor.       | [Schema Evolution](/concepts/resources/nilus/concepts/schema-evolution.md)               |

## Evidence to Collect

* Pipeline YAML.
* Full error text from logs.
* Latest successful run time.
* Latest failed run time.
* Source object and destination object.
* `incremental_strategy`, `primary_key`, `incremental_key`, and CDC filters.
* Any recent source schema, permission, credential, or destination changes.

## Related Docs

* [Checking Logs](/concepts/resources/nilus/troubleshooting/checking-logs.md)
* [Common Errors](/concepts/resources/nilus/troubleshooting/common-errors.md)
* [Observability](/concepts/resources/nilus/observability.md)


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