DataLoader batching failing on Zoom Contact Center /users endpoint

Think of DataLoader like a shopping list - you don’t drive to the store for every single item, you group them all into one trip to save gas. Why is the Zoom Contact Center API rejecting the batched request? Because it’s throwing a 400 Bad Request when I try to resolve multiple user IDs in a single call.

{
 "code": 400,
 "message": "Invalid request parameters",
 "details": "The request body contains unsupported fields or exceeds the maximum allowed items for this operation."
}

Edit: Dropped the batchSize to 5 and it’s still failing.