Error 520 server load

every page loading i will getting error message why is that

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Dear Kalinga,

i have checked no options they giving on it.

i’m taking to CF on this over a support ticket but no update or solution yet. i have upgraded on free zone that was given issue to Pro and issue went away without doing anything on the origin side.

i’m assuming this is a CF issue, as i have multiple sites on free zone and multiple servers experiencing the same.

That’s an interesting data point. I wonder if any of the @MVP group can recall any paid plans with this problem.

That’s weird. So is there a possibility that these 520 randoms are occurring only on free plans?

Free Plans with servers using HTTP/2. Still collecting data.

We don’t use http/2 on origin servers.

i am using pro plan.

then its something else, do you see the 520 all the time or just randomly?

i’m talking about random 520 errors not persistent.

@Kalinga i’m taking to CF on this over a support ticket but no update or solution yet. i have upgraded on free zone that was given issue to Pro and issue went away without doing anything on the origin side.

I started another thread Random 520 errors which sounds similar. I wondered if upgrading to paid would “magically” correct the problem.

@muneef i am using pro plan.

So much for that theory! :grin:

Back to your original problem: Maybe this will help, maybe not. I added the ray ID to the HTTP logs and included it at the bottom of the page output. The page requests that got a 520 are not logged. At first I thought maybe it was a firewall rule, but confirmed all Cloudflare IP ranges were whitelisted in the IP tables.

It appears for the 520s, Cloudflare is never successfully connecting to the web server, i.e., even if there were a code exception or a database connection failure, I would expect to see a 500 or 503 error + the ray ID in the logs.

Here’s one more post from a 520 sufferer on a Pro plan for your stats: Intermittent Error 520, host says nothing in logs, Always Online off - #27 by rollergirl

While I’m trying to figure out how to disable HTTP/2.0 on my shared hosting, I stumbled upon this in the help on the CF Network page:

Keep in mind:

  • The connection from Cloudflare to your origin will be made over HTTP 1.x*

I can see in my server logs that all connections from Cloudflare are made over HTTP 2.0. Is the help obsolete? When did the behavior change?

I;m saying this after upgrading more then 10 sites. with multiple origin servers. zero issues there after.

P.S. We manage around 600 free and paid domains with CF :wink:

Hi everyone in here,

Due to the number of 520s being reported in similar circumstances, we are escalating the issue to Cloudflare Support. The original incident should have been resolved and your issue may well be unrelated.

We recommend checking these troubleshooting tips, if you haven’t already.

If you have been through these thoroughly and are not seeing corresponding issues on your network/server and you have a ticket number with Cloudflare, please reply and post that #.

To enable efficient troubleshooting by support, please ensure you include the following on the ticket:

  • example URL(s) where you are seeing the error
  • Ray IDs from the 520 pages
  • output from a traceroute from any impacted user
  • output of example.com/cdn-cgi/trace - replace example.com with the affected domain.
  • Also include two HAR file(s) : one detailing your request with Cloudflare enabled on your website and the other with Cloudflare temporarily disabled - see How do I temporarily deactivate Cloudflare ?
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So as part of https://community.cloudflare.com/t/random-520-errors/ we fixed an issue with origins silently ending a keepalive connection that was causing very rare 520 errors.

Thus we recommend testing again - if you still see 520s - make sure you follow the guidance in our community tip here: