Website traffic down and getting error

In last 2 days my website traffic went down by 1000 visitors per day. And while login, log out and while taking preview of any post in wordpress. Many times I Received error called >>> “web server is returning an unknown error” please help me.

Don’t create multiple posts on the same topic @articalcontent!

What has that got to do with Cloudflare?

More information required.

Post a screenshot, and/or link to the site with steps to reproduce.