Empty page content for search engines

Hello.
When checking server response, page content:
976

At the same time, direct access to the site from the browser works. Because of this, search engines see empty content on site pages. Please tell me which setting affects this?

One Firewall Rule included: Known Bots - Allow
Development Mode is now active.

Seem your site was hacked. All traffics from search engine will redirect to other page. Search some things like: site.yoursite.tld on any search engine then click on any result to see if it redirect to other page or not?

Hi. Regular checks, protection modules, the site is protected. There is a suspicion of a hosting provider. But they cite problems at Cloudflare. There is no such error on the forum, most likely it is a provider.