Local Realm Data does not sync realm data from local Client (Swift) to Server

[Kamayani_Tiwari]

Local Realm data does not sync from client (Swift) to server via Device Sync.

Steps done:
I am new to Mongo I am trying to implement Atlas Device Sync for my application. Here are the steps I have followed

1. Enabled Flexible Sync with Development mode ON , added queryable fields.
2. Enabled anonymous authentication
3. Schema was generated automatically as changes were done on client side.

Here is the object model

class VLocation: Object ,ObjectKeyIdentifiable  {
    @Persisted(primaryKey: true) var _id: ObjectId
    @Persisted var accuracy: Double?
    @Persisted var address: String?
    @Persisted var timestamp: Date?
    @Persisted var systemId: String?
    @Persisted var eventType:String
    @Persisted var deviceImei: String?
    @Persisted var batteryLevel : Int?
    @Persisted var isDataAvailable:Bool?
    @Persisted var isMoving:Int?
    @Persisted var cacheTimeStamp: Date?
     }

4. Added swift code for anonymous login to Realm with App ID
5. Able to write to realm Vlocation using below syntax successfully

Let locationData = Vlocation()
…. //other data
    location.eventType = “Location”
…//other data
  try! realm.write {
realm.add(locationData)
}

6. Added subscription to be able to upload on server

let configuration = user.flexibleSyncConfiguration(initialSubscriptions: { subs in
            subs.append(QuerySubscription<VLocation> {
                $0.eventType == "Location"
            })
        })


writeToLocation(realm, user)

Observation:

App Services shows below logs and everything seems fine but no document is inserted in VLocation.

Logs:
[
  "Session closed after receiving UNBIND event",
  "Session was active for: 0s"
]
Function Call Location:
US-VA
Query:
{
  "VLocation": "(eventType == \"Location\")"
}
Session Metrics:
{
  "downloads": 1
}

Logs:
[
  "changing query from existing query to new query",
  "Roles selected for sync:",
  "   readAndWriteAll: [ VLocation ]"
]
Function Call Location:
US-VA
Query:
{
  "VLocation": "(eventType == \"Location\")"
}

Is there anything else that needs to be done to be able to successfully upload local realm documents to server?