BYOC Edge 502 Bad Gateway during Zendesk Voice Migration

No idea why this is happening, the Genesys Cloud BYOC Edge is returning a 502 Bad Gateway error when attempting to bridge Zendesk voice interactions. We are in the final stages of migrating our support center from Zendesk Talk to Genesys Cloud CX, and the voice channel is the last hurdle. The Zendesk side initiates the call correctly, and we see the interaction metadata arriving in the Genesys platform, but the actual media stream never connects. The call drops after approximately 15 seconds with a generic network failure on the agent side.

Our architecture involves a custom middleware that translates Zendesk webhook events into Genesys Architect flows. We are using the latest Genesys Cloud SDK for Python (v2.1.0) to handle the API calls. The Edge is deployed in the AWS eu-west-1 region, matching our Zendesk data residency requirements. However, when the Architect flow attempts to route the call to a Genesys agent, the Edge logs show a connection timeout to the media server.

Here is the relevant snippet from the Edge debug logs:

2023-10-27T14:32:10Z ERROR [edge-media] Connection refused to 10.0.5.22:5060
2023-10-27T14:32:10Z WARN [sip-stack] 502 Bad Gateway for call-id: zdk-mig-8842

We have verified that the security groups allow traffic on ports 5060-5061 and the UDP range 10000-20000. The Zendesk ticket-to-interaction mapping works perfectly for chat and email, which makes this voice issue particularly frustrating. Is there a specific configuration in the BYOC Edge settings that differs from the standard public cloud deployment? We are struggling to map the Zendesk call control parameters to the Genesys SIP trunk settings. Any insights on how to debug the media path between the Edge and the Genesys media servers would be appreciated. We are on a tight deadline to decommission the Zendesk voice stack.