[Yandex Cloud documentation](../../../index.md) > [Yandex DataLens](../../index.md) > Troubleshooting > Changing the data source is not available

# [Yandex DataLens] error `Data source modification is not allowed`

`ERR.DS_API.PREVIEW_SOURCE_MODIFICATION_NOT_ALLOWED`

The error means that the user lacks the `Read` permission for the connection used in the data source when attempting to modify the source via an API request.

For example, in the [Public API](../../operations/api-start.md), when the user has no `Read` permission for the connection and attempts to modify the source in a dataset preview request.

Use one of the ways below to resolve the error:

* In your request, use the connection previously saved in the dataset.
* If you need to change the source parameters, request access from the connection administrator. For more on access permissions, see [Managing access to Yandex DataLens](../../security/index.md).