What is the correct way to handle SIP 486 Busy Here during WFM shift swaps?

How do I correctly to handle SIP 486 Busy Here errors when agents initiate shift swaps via WFM self-service during peak hours? We are seeing a spike in failed swap requests correlating with high call volume.

1. Agent A initiates a shift trade with Agent B via the WFM portal.
2. The system triggers an internal notification or status update.
3. Simultaneously, Agent B is handling a high-volume SIP trunk call.
4. The WFM service attempts to ping Agent B’s availability status via a background API call.
5. The SIP stack returns 486 Busy Here, causing the WFM API to timeout and reject the swap request.

We are on Genesys Cloud version 23.4. The issue seems to stem from the WFM service treating a telephonic busy state as a system unavailability for WFM actions. Is there a configuration in Architect or WFM settings to decouple SIP call status from WFM availability checks? We need agents to be able to manage their schedules even when they are technically ‘on call’.

To fix this easily, this is… to decouple WFM state changes from real-time telephony signaling. SIP 486 indicates the media path is occupied, not that the user is unavailable for scheduling logic. The WFM service should not rely on SIP ping responses for availability checks during high concurrency. Instead, configure the shift swap API to read from the users/{id}/state endpoint or the WFM-specific availability API. This bypasses the telephony stack entirely. In Terraform, ensure your WFM resources are defined with correct dependency ordering so that status updates are asynchronous. Use a webhook to trigger the swap confirmation only after the SIP session ends, rather than attempting a synchronous handshake during the call. This prevents race conditions between the media channel and the scheduling engine. The documentation suggests using event-driven triggers for WFM actions rather than polling active sessions.