WFM API 429 Errors During JMeter Load Test

Anyone know why the Workforce Management API returns HTTP 429 Too Many Requests when JMeter pushes 100 concurrent threads? We are testing Genesys Cloud US1 environment. The endpoint is /api/v2/wfm/schedules. The rate limit headers show X-RateLimit-Remaining as 0 quickly. JMeter version is 5.6. We need to understand the specific throughput limits for WFM data ingestion under load.