Why does one single url give 404 on AMP?

Question

Search Engine Optimization

Good afternoon!
Installed on WordPress AMP + AMP for WP.
All pages are working except for one. The page gives 404 when adding amp at the end of the url. Check tool from google - crashes into an error with no explanation.
I made a duplicate of the page, thereby changing the page id - it did not help.
The reason lies precisely in the url. As soon as I change it, everything works immediately. What could be the reason? Maybe there is some kind of validator. How can I find out why amp is not being formed?
Page address: kumantsova.com/price/

Answer 1

cache, the result of the script execution at the given url is cached.