{"Error":"Value cannot be null. (Parameter \u0027source\u0027)","StackTrace":"   at System.Linq.ThrowHelper.ThrowArgumentNullException(ExceptionArgument argument)\n   at System.Linq.Enumerable.Count[TSource](IEnumerable\u00601 source)\n   at Bulev.Library.Products.BookmarksIM.Remove(BaseController controller) in E:\\_disk c\\_work\\_projects\\ZigZagDom\\Bulev.Library.Products\\Bulev.Library.Products\\Models\\Bookmarks.cs:line 63"}