Can't get all list user using REST API when my system have more than 1000 users

[Thanh Bắc]

Step 1 : rest/api/2/user/search?startAt=999&maxResults=1000&username=.

Response return 1 user

Step 2 : rest/api/2/user/search?startAt=1001&maxResults=1000&username=.

When i call above api response api is null. I'm sure my system have more than 1000 users