Random 525 errors for various apps


I have DNS with Cloudflare. I use CNAMEs (orange cloud, ie proxied) to e.g my-app.fly.dev

That works great. However in the past couple of hours I’ve been getting random emails from Cloudflare’s healthchecks saying the status code has dropped from 200 to 525.

Apparently the status code 525 means there was an SSL error. I’m not sure if that 525 is being generated from your system, or from Cloudflare.

I checked the apps and haven’t done any deploys or made any changes, and the “certs list” command shows a certificate is present, added e.g 5 months ago. So as far as I can see that hasn’t changed. Hmm.

Are you aware of anything SSL related changing at your end in the past couple of hours? Not really sure what else could have caused it as I haven’t made any changes to an app or in Cloudflare.


That very well could have been related to the routing issues we had, but it’s weird they manifested as SSL errors: https://status.flyio.net/

Thanks kurt. Sounds like that may be the issue then as nothing else has changed.

I looked up that error on Cloudflare https://support.cloudflare.com/hc/en-us/articles/115003011431-Troubleshooting-Cloudflare-5XX-errors#525error and since the SSL certificate has not changed they say another possible cause can be port 443 is not open on the origin (ie, the fly app in this case).

So perhaps if there was some routing/port issue, that couldn’t be accessed. And so without a SSL handshake, it returned a 525 back.

Ah well, hopefully it’s one of those random things. Thanks!

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Oh that would make sense. They love their error pages. :slight_smile:

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