I try to paginate chronologically by **created\_at** field (type of this field is **timestamp**), but the problem the following query with start\_at return null, despite I have data after the given date (created\_date).

```
  snapshot = await FirebaseHelper.FirebaseContext.firestore()
      .collection("Announcements")
      .orderBy("created_at", "desc")
      .startAt(1617235200000) // --> not work
      .limit(3)
     // .where("created_at", ">", 1617235200000) --> this not work also
      .get();

```

With startAt result is NULL !

Without startAt I got results

[![enter image description here](https://i.stack.imgur.com/jndxA.png)](https://i.stack.imgur.com/jndxA.png)

[![enter image description here](https://i.stack.imgur.com/AB8XV.png)](https://i.stack.imgur.com/AB8XV.png)

From docs: <https://firebase.google.com/docs/firestore/query-data/query-cursors>
[![enter image description here](https://i.stack.imgur.com/JOqDj.png)](https://i.stack.imgur.com/JOqDj.png)

If I use other field for pagination (for example the ID) it works !
This reproduce just with **timestamp** field