Fb Crawler cannot parse the page, what could be the reason?

Question

Facebook

The problem is, fb crawler can't scrape a page by url. Error 404. This is visible when you add a url to a post, as well as when posting a page in fb instant articles.
In the debugger https://developers.facebook.com/tools/debug/sharing/ if you hit the link for the first time with a 404 error, the second time it loads everything without a picture, the third time it loads everything with a picture, including.
WordPress site based on nginx.
Access.log does not give any 404 errors for facebookexternalhit.
In nginx, there used to be a config below, but now I have removed it just in case, facebookexternalhit, in theory, does not block anything.

if ($http_user_agent ~* msnbot|scrapbot) {
  return 403;
}

All opengraph tags are exposed by YOAST. Plugin deactivated activated, to no avail.
Partially managed to solve the problem with a crutch in the footer of the page added

<iframe style="width: 0px; height: 0px; margin: 0px; padding: 0px;" src="https://www.facebook.com/sharer/sharer.php?u=http%3A%2F%2Fwww.mysite.com"></iframe>

When inserting a link into a post on FB, everything works instantly, in Instant Articles there is still a problem (it cannot parse information on the materials viewed everywhere "page not found").
By the way, the problems started when I upgraded the digitalocean droplet to a more powerful one.
Those who have come across, enlighten, what's the catch?