How to Fix Cloudflare Error 521 Server Down (2019)

This is the most common error for all Cloudflare users. When I search How to Fix Cloudflare Error 521 Server Down on the search engine, I didn’t find the exact solution. So I think let’s share details on that. Every user must face this problem once their Cloudflare life. In this case, I have little more experience, as I face again and again.

how to fix cloudflare error 521 server down

What is Cloudflare Error 521:

Here I explain in very simple for better clarification. Cloudflare 521 error is a Server-side error. It basically happens when the server, not response to Cloudflare. The browser connects to Cloudflare but Cloudflare got connection refused from the WordPress server or Web server.

Although our server is in good condition, still the error 521 comes. Mostly it happens with unmanaged servers like VPS or Dedicated Server.

How does it happen?

There is three most common reason for that 521 error occur. This problem occure when

  1. Cloudflare SSL Configuration Setting
  2. The web server process (e.g. Apache or Nginx) isn’t running or has crashed.
  3. Server block Cloudflare IP Adress (Port:80/443)
cloudflare error 521

How to Fix Cloudflare Error 521 Server Down:

Below are three processes to fix this Cloudflare error 521. In my case, the server got crashed. so that I took a new server. If you have an unmanaged server like me, the problem may come often. To face the problem you always have a backup of your website files and Database too.

1) Proper Configuration of Cloudflare SSL:

  • If you want to use Cloudflare SSL then change the setting to Flexible SSL instate of other option.
  • Want to use custom SSL (eg: Let’s Encrypt), change the setting to Full (strict)
  • Otherwise, pause Cloudflare on site.

2) Check The web server process running or has crashed:

  • We need to restart the web server if the server is stopped.
  • Apache: service apache2 restart
  • NGINX: service nginx restart
  • If the above command not working then your server may be got crashed.

What to do if crashed?: If you have backup your website files then destroy the current server, take a new one. otherwise backup your file via terminal and download it via FTP/SFTP and restore. If you need any help just comment here. I will reach you asps.

Also Read: (Easy Method) Login File Manager Without cPanel in WordPress

3) Check Port (80/443) blocked or not:

  • If the command working fine and still not opening your site then you need to whitelist your IP in the server firewall.
  • Here the Link of this solution from Cloudflare: Click Here
  • This process is a boring process. But still, have a try.

What it affect to the Blog?

As we know when this problem comes out, user unable to access our blog URL. They moved to another website. As a result, we lose CTR on the search engine. If the problem stays some hour it will fine. If it continues some days, definitely we lose the search engine rank.


So this is the way how to fix Cloudflare error 521 server down. In my case, my server was crashed and most of the command is not working properly. So i take server and host on that. Some of my sites have cloud backup and some site have to manually backup via a terminal command. Ask me Direct via Facebook messenger, still you facing any problem.

One Response

  1. September 24, 2019

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