521 Webserver down

Hi.
https Is not access.
http is Access.
When https access show message " error 521 web server down.".
but my server is alive…
same server other domain is good access…

plz. help…

Have a look at this:

Same Server Other domain is no problem…
No Firewall…
cloudflare Ip list input Iptables and daemon is restart…

finally same problem.

Do you see any records in the server logs corresponding to when Cloudflare is requesting the site? Perhaps you could track it down that way. Not really a lot else to suggest other than what’s already in the linked article.

Use cloudflare DNS.
On error message on
Off is normal

When Cloudflare is :grey: your website should work with https otherwise when turning CLoudflare :orange: you will get error.

For starters, whats the domain?