The error code
[AirtableError Request failed with status code 429]. Hit Airtable API Rate Limit
comes from Airtable's API. It means that requests have been made too quickly. You can lean more about this here.
If you're using the CSV Exporter automation on a base with a lot of miniExtensions, you could run into this issue, since each extension and automation would make their own requests. If too many of them occur in rapid succession, you see this error.