com.google.firebase.database.DatabaseException Play Console Error

I'm getting the following crash log in Play Console, but I'm unable to find the line which is causing it. The error I'm getting is below

com.google.firebase.database.DatabaseException

com.firebase.ui.database.ClassSnapshotParser.parseSnapshot

Type:

com.google.firebase.database.DatabaseException

Logs:

com.google.firebase.database.DatabaseException: 
at com.google.firebase.database.core.utilities.encoding.CustomClassMapper.convertBean (CustomClassMapper.java:56)
at com.google.firebase.database.core.utilities.encoding.CustomClassMapper.deserializeToClass (CustomClassMapper.java:81)
at com.google.firebase.database.core.utilities.encoding.CustomClassMapper.convertToCustomClass (CustomClassMapper.java)
at com.google.firebase.database.DataSnapshot.getValue (DataSnapshot.java:10)
at com.firebase.ui.database.ClassSnapshotParser.parseSnapshot (ClassSnapshotParser.java:2)
at com.firebase.ui.database.ClassSnapshotParser.parseSnapshot (ClassSnapshotParser.java:2)
at com.firebase.ui.common.BaseCachingSnapshotParser.parseSnapshot (BaseCachingSnapshotParser.java:14)
at com.firebase.ui.common.BaseObservableSnapshotArray.get (BaseObservableSnapshotArray.java:6)
at com.firebase.ui.database.FirebaseRecyclerAdapter.getItem (FirebaseRecyclerAdapter.java:2)
at com.firebase.ui.database.FirebaseRecyclerAdapter.onBindViewHolder (FirebaseRecyclerAdapter.java)
at androidx.recyclerview.widget.RecyclerView$Adapter.onBindViewHolder (RecyclerView.java)
at androidx.recyclerview.widget.RecyclerView$Adapter.bindViewHolder (RecyclerView.java:29)
at androidx.recyclerview.widget.RecyclerView$Recycler.tryBindViewHolderByDeadline (RecyclerView.java:39)
at androidx.recyclerview.widget.RecyclerView$Recycler.tryGetViewHolderForPositionByDeadline (RecyclerView.java:498)
at androidx.recyclerview.widget.RecyclerView$Recycler.getViewForPosition (RecyclerView.java:5)
at androidx.recyclerview.widget.RecyclerView$Recycler.getViewForPosition (RecyclerView.java:1)
at androidx.recyclerview.widget.LinearLayoutManager$LayoutState.next (LinearLayoutManager.java:11)
at androidx.recyclerview.widget.LinearLayoutManager.layoutChunk (LinearLayoutManager.java)
at androidx.recyclerview.widget.LinearLayoutManager.fill (LinearLayoutManager.java:38)
at androidx.recyclerview.widget.LinearLayoutManager.onLayoutChildren (LinearLayoutManager.java:356)
at androidx.recyclerview.widget.RecyclerView.dispatchLayoutStep2 (RecyclerView.java:38)
at androidx.recyclerview.widget.RecyclerView.onMeasure (RecyclerView.java:65)
at android.view.View.measure (View.java:26415)
at android.view.ViewGroup.measureChildWithMargins (ViewGroup.java:7845)
at android.widget.LinearLayout.measureChildBeforeLayout (LinearLayout.java:1552)
at android.widget.LinearLayout.measureVertical (LinearLayout.java:842)
at android.widget.LinearLayout.onMeasure (LinearLayout.java:721)
at android.view.View.measure (View.java:26415)
at android.widget.RelativeLayout.measureChildHorizontal (RelativeLayout.java:735)
at android.widget.RelativeLayout.onMeasure (RelativeLayout.java:481)
at android.view.View.measure (View.java:26415)
at android.widget.RelativeLayout.measureChildHorizontal (RelativeLayout.java:735)
at android.widget.RelativeLayout.onMeasure (RelativeLayout.java:481)
at android.view.View.measure (View.java:26415)
at android.widget.RelativeLayout.measureChildHorizontal (RelativeLayout.java:735)
at android.widget.RelativeLayout.onMeasure (RelativeLayout.java:481)
at android.view.View.measure (View.java:26415)
at android.view.ViewGroup.measureChildWithMargins (ViewGroup.java:7845)
at android.widget.FrameLayout.onMeasure (FrameLayout.java:194)
at androidx.appcompat.widget.ContentFrameLayout.onMeasure (ContentFrameLayout.java:154)
at android.view.View.measure (View.java:26415)
at android.view.ViewGroup.measureChildWithMargins (ViewGroup.java:7845)
at android.widget.LinearLayout.measureChildBeforeLayout (LinearLayout.java:1552)
at android.widget.LinearLayout.measureVertical (LinearLayout.java:842)
at android.widget.LinearLayout.onMeasure (LinearLayout.java:721)
at android.view.View.measure (View.java:26415)
at android.view.ViewGroup.measureChildWithMargins (ViewGroup.java:7845)
at android.widget.FrameLayout.onMeasure (FrameLayout.java:194)
at android.view.View.measure (View.java:26415)
at android.view.ViewGroup.measureChildWithMargins (ViewGroup.java:7845)
at android.widget.LinearLayout.measureChildBeforeLayout (LinearLayout.java:1552)
at android.widget.LinearLayout.measureVertical (LinearLayout.java:842)
at android.widget.LinearLayout.onMeasure (LinearLayout.java:721)
at android.view.View.measure (View.java:26415)
at android.view.ViewGroup.measureChildWithMargins (ViewGroup.java:7845)
at android.widget.FrameLayout.onMeasure (FrameLayout.java:194)
at com.android.internal.policy.DecorView.onMeasure (DecorView.java:1013)
at android.view.View.measure (View.java:26415)
at android.view.ViewRootImpl.performMeasure (ViewRootImpl.java:3609)
at android.view.ViewRootImpl.measureHierarchy (ViewRootImpl.java:2352)
at android.view.ViewRootImpl.performTraversals (ViewRootImpl.java:2644)
at android.view.ViewRootImpl.doTraversal (ViewRootImpl.java:2204)
at android.view.ViewRootImpl$TraversalRunnable.run (ViewRootImpl.java:9003)
at android.view.Choreographer$CallbackRecord.run (Choreographer.java:996)
at android.view.Choreographer.doCallbacks (Choreographer.java:794)
at android.view.Choreographer.doFrame (Choreographer.java:729)
at android.view.Choreographer$FrameDisplayEventReceiver.run (Choreographer.java:981)
at android.os.Handler.handleCallback (Handler.java:883)
at android.os.Handler.dispatchMessage (Handler.java:100)
at android.os.Looper.loop (Looper.java:237)
at android.app.ActivityThread.main (ActivityThread.java:7948)
at java.lang.reflect.Method.invoke (Method.java)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run (RuntimeInit.java:493)
at com.android.internal.os.ZygoteInit.main (ZygoteInit.java:1075)

Could someone please help me understand what is causing this error and how can I resolve this?

This is the model class I'm using

@JsonIgnoreProperties(ignoreUnknown=true)
@Keep

public class Messenger_Model {

String sentTime;

public Messenger_Model(){

}

public Messenger_Model(

        String sentTime

) {
    this.sentTime = sentTime;
}

public String getSentTime() {
    return sentTime;
}

public void setSentTime(String sentTime) {
    this.sentTime = sentTime;
}
}

And this is the DB structure