Predictive Routing 500 Internal Server Error during Zendesk Skill Mapping

Trying to make sense of why the Genesys Cloud Predictive Routing API returns a 500 Internal Server Error when attempting to map Zendesk agent skills to Genesys Cloud Roster Group capabilities.

We are in the final stages of migrating our support operations from Zendesk to Genesys Cloud. The digital channel migration is complete, and ticket-to-interaction mapping is working perfectly. Now we are tackling the voice and chat routing logic.

In Zendesk, we used simple tags and custom fields to define agent expertise. We exported this data and are using the /api/v2/architect/flows endpoint to create a new routing flow. The flow itself validates successfully in the Architect UI.

However, when we attempt to assign the flow to a Queue with specific Predictive Routing settings via the /api/v2/routing/queues endpoint, the server crashes. The error response contains no useful payload. Just a generic 500 status code.

This happens specifically when the JSON payload includes a routing object with strategy set to PREDICTIVE. If we switch the strategy to LONGEST_IDLE_AGENT, the API call succeeds without issue.

We are using the Genesys Cloud Java SDK version 12.0.0. The environment is the EMEA-1 region. Timezone is Europe/Paris. Our test users have the routing:queue:admin permission set correctly.

The Zendesk workflow was straightforward. Just tag-based routing. Genesys seems much more complex. The documentation mentions that Predictive Routing requires historical data or a specific model training period. We have been live for only two weeks.

Is this a known limitation for new tenants? Or is there a specific configuration in the Roster Group that is missing?

We need this fixed before the full cutover on Friday. Any insights on what triggers this specific 500 error in the routing API would be greatly appreciated.

Thanks in advance.