finduser query returning nil Parse and swift

Question

I'm trying to find which user commented on the blog post. but it always returns nil and total objects 0, i'm not sure what am i doing wrong. This is my code to get the user's username

var finduser:PFQuery = PFUser.query()
finduser.whereKey("ObjectId", equalTo: commentclass.objectForKey("byuser").objectId)
finduser.findObjectsInBackgroundWithBlock { (objects:[AnyObject]!, error:NSError!) -> Void in
    if error == nil {
        if let aobjects = objects {
           let puser = (aobjects as NSArray).lastObject as? PFUser
            cell.userName.text = puser?.username
            println(puser) // returns nil
            println(aobjects.count) // returns 0
        }
    }
}

Answer 1

It should be objectId and not ObjectId, also make sure there is no ACL set for the user object that might prohibit the requesting user from seeing this object.