System.Web.Services.Protocols.SoapException: Server was unable to process request. ---> NHibernate.MappingException: Invalid mapping information specified for type Test.SyncAPI.Contacts.DAO.User, check your mapping file for property type mismatches ---> System.InvalidCastException: Unable to cast object of type 'NHibernate.Collection.Generic.PersistentGenericBag`1[Test.SyncAPI.Contacts.DAO.Group]' to type 'System.Collections.Generic.List`1[Test.SyncAPI.Contacts.DAO.Group]'.
   at (Object , Object[] , SetterCallback )
   at NHibernate.Bytecode.Lightweight.AccessOptimizer.SetPropertyValues(Object target, Object[] values)
   at NHibernate.Persister.Entity.AbstractEntityPersister.SetPropertyValues(Object obj, Object[] values)
   --- End of inner exception stack trace ---
   at NHibernate.Persister.Entity.AbstractEntityPersister.SetPropertyValues(Object obj, Object[] values)
   at NHibernate.Impl.SessionImpl.InitializeEntity(Object obj)
   at NHibernate.Loader.Loader.InitializeEntitiesAndCollections(IList hydratedObjects, Object resultSetId, ISessionImplementor session)
   at NHibernate.Loader.Loader.DoQuery(ISessionImplementor session, QueryParameters queryParameters, Boolean returnProxies)
   at NHibernate.Loader.Loader.DoQueryAndInitializeNonLazyCollections(ISessionImplementor session, QueryParameters queryParameters, Boolean returnProxies)
   at NHibernate.Loader.Loader.DoList(ISessionImplementor session, QueryParameters queryParameters)
   at NHibernate.Loader.Loader.List(ISessionImplementor session, QueryParameters queryParameters, ISet querySpaces, IType[] resultTypes)
   at NHibernate.Impl.SessionImpl.Find(CriteriaImpl criteria, IList results)
   at NHibernate.Impl.SessionImpl.Find(CriteriaImpl criteria)
   at NHibernate.Impl.CriteriaImpl.List()
   at Test.SyncAPI.Contacts.WebServices.ContactsWebService.Logon(String strLogon, String strSecret) in D:\Projects\Test\ContactsWebService.asmx.cs:line 85
   --- End of inner exception stack trace ---