Custom post type for gallery as Attachment Page

Hello.
I have created and added the post, attached a few pictures and put the gallery in the content. gallery inserted as Attachment Page.
when I click on the pictures gallery in the post, I get a page not found.
link looks like:
https://site.ru/custom_post_type/post_name/link_url_from_attacments/ – not work
but when I remove the custom_post_typ from link i see the picture
https://site.ru/post_name/link_url_from_attacments/ – work

how I get to work a link https://site.ru/custom_post_type/post_name/link_url_from_attacments/?
thank you.