Blank WAF page, no add button, no my rules

Blank WAF page, no add button, no my rules, cache cleared, tried different browsers.

Yesterday this page was displayed normally, but today neither reloading the page with disabled cache, nor changing browsers - nothing helps, the page is empty. But the rules themselves work and the site is displayed using these rules, which are not on the account page now.

I tried browsers of the latest versions: Edge, FireFox, Chrome, Yandex. There are no add-ons or plug-ins in the browsers - they have just been installed.
I turned on incognito mode, disabled page cache in developer mode - nothing helps, the page is empty.

Forgot to add - there are 10 other sites in the same account, they have no problem with this page, only this one site has a problem.
Of all the sites, this site in the account is the only CDN (domain characters are not English).