Sync between Mongo Stitch and Local DB

Question

I have setup MongoDB Atlas Server using Stitch and inserting data from an application using sync.insertone, it is inserted into the remote MongoDB Collections and also inserted into local database storage.

But when I delete the application and again installed it, the data from the server is not getting synced with local db. Any idea how to achieve this?

When I'm finding the data using collection.find() it only returns me the data from local db.

I'm using MongoDB Stitch SDK for iOS/Swift.

This is my sync configuration with the collection

 userCollection.sync.configure(conflictHandler: DefaultConflictHandler<M_User>.remoteWins(),
                                  changeEventDelegate: nil,
                                  errorListener: nil)