The task's state must be pending:complete_client_action and its client_action must match the action parameter to make this request.

The request body should define an message describing the error that caused the client to fail the action:

{
  "message": "<your-error-message"
}

After a successful request, the task's state is set to running while the original file and all related data are deleted from the Aluma service and then failed once that is done.

The task remains available for around 72 hours in its final state so your code can check its state if necessary using a Get Task or List Tasks request.