Possible to fetch user details from another field

Android SDK
I’m trying to fetch the user details from Realm db by querying on one of the fields, for some reason the result is always null.Anything i’m missing

User userModel = realm.where(User.class).equalTo("firebaseAuthUserId", firebaseID).findFirst();
                    if(userModel != null && userModel.isValid()) {
                    else {
                        completionUser.onFail("User does not found");

@San11111 : Have you tried exporting Data to realm studio to check if you have data or not? Query looks good to me.

On side note: If you are using Realm Sync, then in that case also verify getSyncConfig parameter (partition key) to get correct instance of Realm.

Let me tell u the complete scenario:
We have old user data in Realm db and have migrated that db to Realm mongodb.
When the old user tries to login it will fail since that user is not present in Auth of Realm.
Forecefully register that user in Auth, use the above query to fetch the user details based on the primarykey of user table and login
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