Genesys Statistics API returning empty queue data for real-time observation

Trying to grab real-time queue stats like waiting count and available agents, but the response is always empty.

curl -X GET "https://api.mypurecloud.com/api/v2/analytics/queues/realtime" \
-H "Authorization: Bearer <token>"

The data array comes back null even though the queue is active. Am I missing a query parameter?