HostError 523

I set up the sites a long time ago. But 3 days ago, problems started with the sites - error 523.

Hosting RU-CENTER.

The IP address is registered from the hosting settings. Matches 100%.

The hoster himself says - “We don’t have any problems. Cloudflare Entry”

Several sites started giving error 523. The IP address of the site in the DNS settings on Cloudflare is specified correctly. When checking through the diagnostic center, there are no errors other than DNSSEC. But I don’t plan to use DNSSEC either.

The hosting provider says - we have no errors…

Let’s call The Boys, @MVP - no idea when Cloudflare throws a 523

Occurs quite randomly (, my best guess would be that your server intermittently blocks Cloudflare requests, but I’d still not expect a 523 :man_shrugging:t2:

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Attempting to traceroute to that IP also throws an error from a handful of colos I tried.

"error": "Could not gather traceroute data: Code 2",

Tried it from Krasnoyarsk, RU, Singapore, SG, Tokyo, JP and they all failed - but Los Angeles, CA, US can reach it.



Cloudflare throws error code 523 when there’s literally no route to the origin address. This can happen due to BGP withdrawals or if the origin is a reserved IP addresses.


@KianNH, @albert, yeah it was somewhat my understanding too, that it was routing related (though I wasn’t sure, hence the cavalary call :woozy_face:) but intermittently? The route works, a couple of seconds later it doesn’t, and then it works again?

Unless, referring to @KianNH’s screenshot, the host intermittently drops the route on their side for a couple of seconds.

Je n’ai aucune idée.

a few seconds later

Seems like it!

Running the same traceroutes over and over shows it works, fails, works, fails, etc

Fun times with routing

Out of curiousity, on which page did you find this beautifully crafted 523 screenshot?

Tried 354 ‘colos’ and got 354 Could not gather traceroute data: Code 2

Well, that’s cool.

For everyone, without exception. The hoster says, I quote - “There are no problems with the hosting service from our side, we recommend that you contact Cloudflare so that they diagnose from their side.”

Well, @KianNH’s debugging seems to be pretty clear on that, your host might simply have intermittent routing issues. Send them a link to this thread along and point out @KianNH’s and @albert’s response.


Thanks! I’ve already sent it.

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