fetch data from strapi 4 with populate and filter

i am using strapi 4. I want to fetch data with ** populate parent** of table **features ** is null.it will works when i use API:/projects?populate[features][populate]=parent

but when i use this API to get data with parent of features is null,/projects?populate[features][populate]=parent&filters[features][parent][$null]=true

it will be log an error:{"data": null,"error": {"status": 500,"name": "InternalServerError","message": "Internal Server Error"}}enter image description here

So what i need change in my API to do this?