Error 520 Web server is returning an unknown error

I am using Woocommerce and have been using Cloudflare for the past 1 year.

I recently reinstalled woocommerce and upgraded my website. soon enough I started getting this error 520

I have tried everything from disabling cache to resetting it. The error ONLY Comes in the admin panel ( my website is accessing fine (

This error is VERY VERY FREQUENT now and I am unable to work. Please help. I have the HAR file and following is the Ray ID: 43bad97dbdfa3066 • 2018-07-17 07:03:35 UTC

please help.

It sounds like the new installation of WC is causing CF to rebuild it’s cache. During that time all requests come from the same IP (CF’s). So your firewall is blocking the flood of requests, giving back 520s. Have your hosting provider whitelist CF’s IP addresses to get around this.

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Thanks Jules for your reply… where can I find CF’s IPs ? I will certainly them allowlisted

Another point, I have already flushed the Cache in CF - should it still show such errors ?

All their Proxy Server IP addresses are here:

Jules’ point is that flushing the Cloudflare causes these errors as your site gets a lot more hits from Cloudflare’s small range of IP addresses. And, in turn, triggering the firewall block.

There’s still chance there’s some other error, and you’ll have to check your server logs or ask your hosting provider if the firewall is blocking these requests.

Got it ! thanks Sdayman

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