Issue with 522 Errors

We are seeing multiple sites on multiple servers getting 522 connection timeout errors. The servers are shared so there are multiple clients setup on a single server. The weird thing is we are only having an issue with one site on that server and all the rest of the sites are working fine. Our servers are in Azure and recently the only sites we have been having issues with are ones that are in Australia. We have tried to restart IIS and reboot the server but that doesn’t seem to help. Is there anything else we can do to resolve this? We don’t have any rate limiting setup on these servers. I know that’s a recommendation for a possible fix.

Hm, are there any Firewall, or physical switch issue at origin host (IIS) or at Azure maybe?

Due to Cloudflare, on the below link we can check for any issues so far:

Does anything changes if you Pause Cloudflare for your domain?
Or temporary switch the :orange: cloud DNS records to :grey: cloud?

Below articles can provide more information about this error type:

Have you allowed Cloudflare IP addresses to connect to your new host/origin?
Maybe you need to allow Cloudflare IP addresses to connect to your host/origin server, if not already:

Cloudflare IPs list can be found here:

How about your web application?, does it work on a port which is compatible with Cloudflare as follows in the below article:

May I also ask if you have got an SSL certificate for your domain and your sub-domain(s) installed at your host/origin server?

Can you also re-check what option have you got selected under SSL/TLS tab at Cloudflare dashboard? Is it Flexible, Full SSL, Full (Strict) or something other?

Could you try to inspect if there is some packet loss by instructions from below?:

There are Network Security Groups attached to the servers which is a basic firewall

I’ve setup a firewall rule to all all the cloudflare proxy ip’s inbound using any protocol.