Returned when you exceed the token-bucket budget for an endpoint class. A retry_after_seconds hint is included. 
{ "error": { "code": "partner_rate_limited", "message": "rate limit exceeded", "retry_after_seconds": 0.42 } }
Fix — back off for at least retry_after_seconds, then retry with a fresh nonce and signature. Prefer the paginated GET /fleet over per-crew polling. See Rate limits.