Exception Error

Not sure why were receiving this exception error. Any ideas? Where trying to filter for results for a specific domain and status that equals active.

var notificationfilters = new Dictionary<string, object>
{
{"Domain",new MailAddress(App.Current.Properties["user_Email"].ToString()).Host},
{"Status","Active" }
};
PodioAPI.Utils.PodioCollection<PodioAPI.Models.Item> itemCollectionNotifications = podio.ItemService.FilterItems(15069505, 10, null, notificationfilters);