Error 520. Web server is returning an unknown error

Website, Application, Performance DNS & Network
2

I am really sorry to hear this.

Nevertheless, I am afraid it’s the issue could be with the SSL for all of them, but it could be that I am wrong at least a bit about your issue.

Let’s go step-by-step, just in case :slight_smile:

Furthermore, if you integrated eZoic, therefore any changes you have to made using their interface (not through the Cloudflare dashboard).

Unfortunately, there are also topics here where people try to setup eZoic and have had issues with which I can find out by using search :search: :

Regarding Cloudflare 520 error, may I suggest you to try looking into below articles to troubleshoot the issue:

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 … )?

Here is a way to re-check if you correctly setup the SSL for your domain with Cloudflare:

Regarding available SSL options at Cloudflare dashboard, check here:

If any other issues appear, follow the needed steps for troubleshooting from article below:

In case you do not have an SSL certificate, you can use Cloudflare SSL, if so, kindly make sure you follow the instructions as follows on the below article to setup an SSL certificate using Cloudflare CA Origin Certificate:

Furthermore, do not skip below step and kindly re-check if Cloudflare is allowed to connect to your origin host to as follows in the below article:

Nevertheless, Cloudflare IP addresses list can be found here:

Here are some helpful information and useful tips regarding error 503:

Could you post a screenshot of the error you receive?
May I ask are this 503 errors comming from origin host/server or Cloudflare?

What happens if you temporarly switch to :grey: cloud (DNS only) or Pause Cloudflare on your Site ?

As far as I use Cloudflare, if you get an error 503, it should be from your host/origin server as described at the article below.

May I also ask if you have tried contacting your hosting provider?

May I ask have you checked the suggestions from the below article?:

Due to this error, obviously you are having a situation where:

  1. The origin host for your domain does not work over HTTPS
  2. The SSL certificate is not being installed or is not a valid one for your domain
  3. Wrong SSL option being selected in Cloudflare dashboard on SSL/TLS tab
  4. Possible use of a port for your app on your domain which is not compatible and supported with Cloudflare while using :orange: cloud (proxy mode) for that hostname (DNS record)

Helpful articles here:

Last but not least, kindly have a look here for more information regarding correct SSL settings:

Ports list compatible and supported when using :orange: cloud (proxy mode) on Cloudflare can be found here:

2 Likes