How do I change the dns, (asmecbra.com.br), for precise use the cloudflare for the email. I changed the dns where I registered the domain, and there I put it from webhost, but when I change through cloudflare, my site goes offline.
It will go offline until you complete the tutorial.
Which tutorial? You say about cloudflare? Concludes more than 12 hours ago.
What is the average time?
You have to switch name servers and DNS and that causes your site to go down until you have finished the tutorial.