代码400 -资源收集过滤错误在Magento Rest API

这是我以前使用过的代码，它工作得很有趣，但现在我收到了一个错误说"{'"messages'":{'"error'":[{'"code'":400,'"message'":'"Resource collection filtering error.'"}]}}"

                FilterExpression filterex = new FilterExpression("status", ExpressionOperator.@in, "Pending");
                filterex.FieldName = "status";
                filterex.FieldValue = "processing";
                filterex.ExpressionOperator = ExpressionOperator.@in;
                Filter filter = new Filter();
                filter.PageSize = 10;
                filter.FilterExpressions.Add(filterex);

这是URL:

{http://sample.test.com/api/rest/orders?filter[0][attribute]=status&filter[0][in]=processing&limit=10}