Predictive Dialer Error 400: Zendesk Ticket Mapping

I’ve spent hours trying to figure out why the outbound dialer fails when mapping Zendesk tickets.

Background

Migrating Zendesk voice tasks to Genesys Cloud outbound campaigns. Using the genesys-cloud-purecloud-iot SDK v1.12.0.

Issue

POST /api/v2/outbound/campaigns returns 400 Bad Request. Error: contactListId must be a valid UUID. The Zendesk ticket ID mapping seems correct.

Troubleshooting

Verified the UUID format. Checked API docs for v2. Still stuck on this validation error. Any tips?