wagtail.search.backends.base.OrderByFieldError: Cannot sort search results with field "page_ptr". Please add index.FilterField('page_ptr') to Model

Question

I'm getting error below when trying to both search and order queryset in wagtail admin.

wagtail.search.backends.base.OrderByFieldError: Cannot sort search results with field "page_ptr". Please add index.FilterField('page_ptr') to Article.search_fields.

I've already added index.FilterField('page_ptr') to my model, but still getting that error. I can see it it search fields of my model:

 ...
 <SearchField: short_description>,
 <wagtail.search.index.RelatedFields at 0xffff922eb730>,
 <wagtail.search.index.RelatedFields at 0xffff922eb5b0>,
 <wagtail.search.index.RelatedFields at 0xffff922eb490>,
 <FilterField: page_ptr>]

Using wagtail==2.16.3