When I call the user deletion endpoint with a single user id I am successful - https://amplitude.com/api/2/deletions/users

However, when I add multiple ids I keep getting the error - Nothing scheduled due to invalid amplitude/user ids for app xxxxxx

This is the body of my post request:

{
    "user_ids": [
        xxx,
        xxx
    ],
    "ignore_invalid_id": "true",
    "requester": "xxx@xxx.com"
}