Why does that appear error 520 when visiting this URL “https://www.worldtest.win/wp-config.php”
It’s not server error. This is wordpress site. .htaccess file is also clean. Asking about, does this appear every wordpress site when using cloudflare?
Which of the suggested steps in the article did you follow?
The things I can fix.
I also contact hoster. They was saying, it’s cloudflare error. So contact cloudflare support team.
The error is displayed by Cloudflare but it is not a Cloudflare error. Your webserver returns an error and so Cloudflare cant display anything. Why that happens is unclear and you’d need to follow the steps outlined in the linked article to find out. You most probably have something misconfigured.
Assuming that your server IP is
x.x.x.240, it would seem as if your account is suspended by your host. Opening
https://www.worldtest.win seems to confirm that as well.