Dealing with a very strange bug here with the Outbound campaign API. Using JMeter 5.6 to simulate high volume dialing requests against /api/v2/outbound/campaigns. When concurrent threads exceed 300, the gateway returns 503 Service Unavailable immediately.
POST /api/v2/outbound/campaigns HTTP/1.1
503 Service Unavailable
This happens before any actual calls are placed. Is there a specific rate limit for campaign creation that triggers this early? Need to adjust my test plan.