CXone v2 Reporting API: Real-time queue stats endpoint 400 error

Trying to pull live queue stats via /api/v2/analytics/queues/realtime. Passing queueIds in the query string but hitting a 400 Bad Request. The payload looks right based on the Swagger spec.

GET /api/v2/analytics/queues/realtime?queueIds=123456&interval=PT1S

Response body just says Invalid query parameter. The docs don’t mention any specific format quirks for the queueIds list. Am I missing a header or is the endpoint deprecated?