I tried these methods. but the result is still the same. When Cloudflare is turned off, the site opens. When Cloudflare is open, I get the error 521. For example, hasaneryilmaz.net and fatihmoda.com.tr are connected to the same hosting. Cloudflare is closed on hasaneryilmaz.net Cloudflare is on at fatihmoda.com.tr . While one site is opened, the other site is not.