Site DOWNS

On the same origin host / server, or?
Maybe some maintenance at the hosting provider or network?

Please follow the steps in this post to solve your problem:

The site is working for me, at least for now as testing:

Before moving to Cloudflare, was your Website working over HTTPS connection?

May I ask what SSL option have you got selected under the SSL/TLS tab at Cloudflare dashboard for your domain ( Flexible, Full, Full Strict … )?