520 error with OpenCart 3 only on information pages

Hello, Community!

I’ve encountered a never seen before issue related to my cloudflare. I haven’t seen such issue in the past few months I’ve been using cloudlfare.

Issue description:

  • 520 error on specific pages only
  • these are only “information” type of pages
  • the issue is flagged by Google search console today with “Crawled, but site with no content” issue as well
  • I can’t access those pages either when cloudlfare is on, but my hosting support can
  • they checked error logs and no such entries related present or anything suggesting any issues on host side
  • pausing cloudlfare makes the issue go away

An example of such pages affected:

Cloudflare Ray ID: 891458a0be01c31a

I attach a screenshot about the error.

Hi,

Thank you for reaching out to us. Sorry to hear that you are experiencing some difficulties here.

A [520 error] (Troubleshooting Cloudflare 5XX errors · Cloudflare Support docs) happens when your origin returns a response that is unexpected.

There are two key instances where this can happen in my experience:

  • Your web server or networking equipment (Firewall, Load Balancer) reset the TCP connection after it was established. Sometimes when a web server crashes it will reset the connection. Check your web server access/error logs for the timescale that the error occurred in and look for any error messages.

  • Your web server returned an invalid response that exceeded our limits. Often this can happen if your web server is returning too many/too large headers. This is often caused by runaway scripts that return too many cookies, for example. The Code Igniter PHP framework has some known bugs around this too.

I went ahead and checked our logs for the past 24 hours and can see there were no further 520 errors during this period.

It is likely that there was a temporary problem at your origin during the period those errors were reported, and one or more of the instances listed above was occurring at your origin. However as this is no longer occurring it is difficult to pinpoint a root cause. I recommend checking with your hosting provider/system administrator to check if there were server issues during the time those issues were reported, reviewing your web server access/error logs would be a good place to locate this information.

Can you please let us know if you’re still experiencing this issue? If you do experience this again please do get in touch and we’ll be happy to investigate this further for you.

Hello,

Thanks so much for replying to my issue and looking into it.

As I tried to mention in my initial message - sorry if I didn’t word it specifically enough - I had my web server access/error logs checked for the timescale and nothing was found related to this issue.

Cloudlfare is paused because of the errors. I once again re-enabled it to check the problem in the past few minutes and issue is the same. And again nothing related whatsoever in the server logs.

Kind regards,
Tib