How to view an AMP page generated by a WP plugin?

Question

Accelerated Mobile Pages

Greetings.
Plugin AMP for Wordpress
is connected Mode - "Reader", the required post type is selected, but it's not possible to switch to the amp version, a 301 redirect to the regular version occurs.

The redirect is in the plugin, because its deactivation eliminates the redirect from the same url, we get 404, as expected.
I activate the plugin again - again 301 redirect, example url:
site.ru/page/amp - I want to open this page
site.ru/page - but there is a redirect here Tell me

what's the matter, how to open the AMP version of the page?