Assuming you all have configured a CNAME for
proxy.klickpages.com.br, the explanation would be quite simple and is actually exactly what the error message you all received is saying.
The machine in question simply is not reachable -> sitemeer.com/#proxy.klickpages.com.br
I am afraid this is something you need to clarify with your service provider/host. Cloudflare cant do anything here.