Retrieve media for a post

Mine worked with this exact query:

https://localhost/wp-json/media?filter[post_parent]=29749

I used the attachments plugin to associate media with the post.
https://github.com/jchristopher/attachments/#attachments

antenando I have try as you say, but it doesn’t work.
The result returns me all media attachments not one or two, which is connected with the post.
Have you test it? How its work?
THanks