Error 521 web server down only when editing Wordpress posts (Cloudflare + WP Bakery + WPML)

Hi there,

I see lot of people having the same issue, Error 521 on wordpress sites using Cloudflare.
In my case everything works smooth but when I try to update a post, the website get unstable… slow and I get lots of 521 errors.

When I deactivate Cloudflare everything works fine again.
At Dreamhost they say it’s a Cloudflare issue.

My website is:

I have not much knowledge, can anybody help me to isolate the issue?
Thanks a lot.

Do you have security plugin installed on WP?

Not really, why?

One way that could happen is your server blocks access to some URLs (here URLs related to administrative tasks) when the request comes from CF network.

Every suggestion in this article points to the origin server blocking requests, and there should be some evidence in their logs:

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I redirected this article to my hosting provider support and it seems there is no issues on their side… so for now I didn’t have any other option than stop using Cloudflare when developing my website.

I have some more insights in case anyone experience the same problem.

I use Cloudflare for a Wordpress site with 2 plugins: WP Bakery (visual composer) and WPML (translation plugin).

When I have Cloudflare + WP Bakery + WPML I get web server down errors when editing pages/posts, if I deactivate 1 of these 3 elements my website works fine.

With this info my host provider finally found the solution:

Default PHP values were:

Memory 64
input time 30
max execution time [120]
max input vars [1000]

And they changed it to:

memory_limit = [128]
max_input_time = [300]
max_execution_time = [300]
max_input_vars = [3000]

I contacted them a few times before and they insisted it was a Cloudflare error, so in case anybody gets those errors… just insist with your hosting provider.


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