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.