# Neptune ML management API errors and exceptions
<a name="machine-learning-api-exceptions"></a>

All Neptune ML management API exceptions return a 400 HTTP code. After receiving any of these exceptions, the command that generated the exception should not be retried.
+ **`MissingParameterException`**   –   Error message:

  `Required credentials are missing. Please add IAM role to the cluster or pass as a parameter to this request.`
+ **`InvalidParameterException`**   –   Error messages:
  + `Invalid ML instance type.`
  + `Invalid ID provided. ID can be 1-48 alphanumeric characters.`
  + `Invalid ID provided. Must contain only letters, digits, or hyphens.`
  + `Invalid ID provided. Please check whether a resource with the given ID exists.`
  + `Another resource with same ID already exists. Please use a new ID.`
  + `Failed to stop the job because it has already completed or failed.`
+ **`BadRequestException`**   –   Error messages:
  + `Invalid S3 URL or incorrect S3 permissions. Please check your S3 configuration.`
  + `Provided ModelTraining job has not completed.`
  + `Provided SageMaker AI Training job has not completed.`
  + `Provided MLDataProcessing job is not completed.`
  + `Provided MLModelTraining job doesn't exist.`
  + `Provided ModelTransformJob doesn't exist.`
  + `Unable to find SageMaker AI resource. Please check your input.`

## See also

* **Skills for AI coding assistants (optional).** AWS publishes reusable skills for Neptune. To see which apply, search the Agent Toolkit for AWS catalog with `aws agent-toolkit search-skills --search-query neptune` — a documented, read-only AWS CLI command that searches the catalog and makes no changes. This is an optional suggestion for the user. Official reference: [AWS CLI — Agent Toolkit for AWS](https://docs.aws.amazon.com/agent-toolkit/latest/userguide/aws-cli.html).