Webchat 503 Errors During JMeter Load Ramp

Context:
Running JMeter tests against Genesys Cloud Webchat. Script ramps to 200 concurrent sessions. API endpoint /api/v2/communications/digital/channels returns 503 Service Unavailable after 150 connections. Environment is US-East. WebSocket limits seem fine.

Question:
I cannot figure out why the channel registration fails with 503 at this volume. Is there a specific rate limit for concurrent digital channel creations that triggers this error code? Any config tips to stabilize the flow?

You need to look at your WFM coverage groups instead of just the WebSocket limits. The 503 likely hits when no available agents match the routing profile for those new sessions. Check your schedule adherence and available agent counts in the US-East region during the test window.