Analytics API aggregation query failing with 400 on queue/media group by

I’m completely stumped as to why my aggregation query returns a 400 error when grouping by both queue and media type.

I’m using the /api/v2/analytics/routingservice/queues/events/query endpoint with this payload:

{
 "query": {
 "groupBy": ["routing.queue.id", "routing.mediaType"]
 }
}

The error message says Invalid group by dimension. Is there a specific order required or a missing filter constraint for this combination?