Cloudflare "Error 525 SSL handshake failed" on Hetzner server
Hi. I have this weird issue since early January.
I am hosting a domain on Hetzner server with multiple subdomains. Sometimes I got
Error 525 SSL handshake error and usually a reload will make that error go away.
I was using the same server, the same domain, the same Nginx configurations before this and I had to reinstall the server due to a problem and after that, I intermittently getting this 525 error code.
What I have tried:
- Upgrading and downgrading Nginx
- Enabling debugging in Nginx log, nothing get logged when this error shows up
- Deleting origin cert in Cloudflare and regenerate them
- Using letsencrypt cert
- Rebooting the server
There are few other things but I cannot recall.
I cannot think any differences between before and after reinstall. After reinstall, I got less files because I cleaned up, and I have IPv6 enabled. I disabled IPv6 before this and leave it enabled after reinstalling. I have tried allowing Nginx to only listen on IPv4, but it still happen.
Also I can access my server fine without Cloudflare proxy. This issue only happen sometimes when I turn on the proxy.
Anyone got an idea how to debug this? I have been patient for so long. I contacted Cloudflare but they suggest me to use FLEXIBLE **SSL Mode instead of **FULL which I am using now. I have no problem trying that but at least I want to pinpoint the cause first.
Thanks in advanced!
- Hetzner auction server, 6TB Disk, 32GB RAM
Sorry for my bad English