2007: Attachment not ready.
The attachment's bytes are still being captured.
HTTP status: 409.
The attachment exists but its capture from the channel has not completed, so there are no bytes to serve yet. The response carries a one-second Retry-After.
Troubleshooting
Section titled “Troubleshooting”- Wait error.retry_after seconds and retry the same GET /v1/attachments/{attachment}/content.