An error occurred while attaching module (Dynamicweb.Frontend.Content)

System.NullReferenceException: Object reference not set to an instance of an object.
   at Dynamicweb.Content.ParagraphPermissionService.GetPermissionForUser(User user, Int32 paragraphId, Permissions permissions, PagePermissionLevels level, Boolean includeEveryone)
   at Dynamicweb.Content.ParagraphPermissionService.GetPermissionForUser(User user, Paragraph permissionObject, PagePermissionLevels level)
   at Dynamicweb.Content.ContentPermissionHelper.HasAccess[T](T permissionObject, PagePermissionLevels pagePermissionLevel)
   at Dynamicweb.Content.ContentPermissionHelper.HasAccessToParagraph(Paragraph paragraph, PermissionLevel permission)
   at Dynamicweb.Content.Items.Queries.Repository.GetParagraphs(Boolean checkPermissions, List`1 effectiveItemTypes, List`1 allPages)
   at Dynamicweb.Content.Items.Queries.Repository.SelectByParentPageIds(IEnumerable`1 parentIds, Query query, Boolean includeParagraphs, Boolean includeChildItems, Boolean checkPermissions, Boolean includeInheritedItems)
   at Dynamicweb.ItemPublisher.Frontend.GetItems()
   at Dynamicweb.ItemPublisher.Frontend.List()
   at Dynamicweb.ItemPublisher.Frontend.GetContent()
   at Dynamicweb.Frontend.Content.GetModuleOutput(Paragraph paragraph, PageView pageview)