Analytics Aggregates query returns empty results for custom intervals

Trying to pull conversation volume for a specific queue using a custom interval in the analytics aggregates query. The endpoint is /api/v2/analytics/conversations/aggregates, but the result set is always empty even though I know there was traffic. Here is the payload I’m sending.

{
 "interval": "2023-10-01T00:00:00.000Z/2023-10-02T00:00:00.000Z",
 "groupings": ["queue"],
 "select": ["conversation.count"],
 "where": "queue.id = '12345678-1234-1234-1234-123456789012'"
}

Am I missing a required parameter or is the interval format wrong?