Looking for advice on WebRTC softphone 503 Service Unavailable errors during JMeter load test. Environment is US1 with Genesys Cloud SDK v2.8. Running 500 concurrent WebSocket connections against /api/v2/foundations/websockets. Handshakes succeed initially but drop after 60 seconds. JMeter logs show 1006 Abnormal Closure. Any insight on WebSocket connection limits or timeout configurations for high concurrency?