Wondering how to resolve CloudFlare error 525 SSL handshake failed? We can help you.

As part of our Server Management Services, we assist our customers with several CloudFlare queries.

Today, let us see how our Support techs resolve this error.

How to resolve CloudFlare error 525 SSL handshake failed ?

Typical, error looks as shown below:

Error 525: SSL handshake failed

Error indicates that the SSL handshake between Cloudflare and the origin web server fail.

This only occurs when the domain is using Cloudflare Full or Full (Strict) SSL mode.

This is cause by a configuration issue in the origin web server.

Today, let us see the steps followed by our Support techs to resolve it:

1. Firstly, make sure you have a valid SSL certificate install on your origin server.

To display your origin certificate, replace 203.0.113.34 with the origin IP address of your web server & replace www.example.com with your domain and host name:

$ curl -svo /dev/null https://www.example.com --connect-to ::203.0.113.34 2>&1 | egrep -v "^{.*$|^}.*$|^* http.*$"

2. Then, check with your hosting provider to make sure they’re listening on port 443/whatever other port 106 you are using.

3. Next, check to make sure your origin server is properly configure for SNI 1.9k.

4. The cipher suites 469 that Cloudflare accepts 477 and the cipher suites that the origin server supports do not match.

Review the cipher suites your server is using to ensure they match what is supported by Cloudflare.

5. Next, if you are the site owner and you’re only seeing errors intermittently, this suggests the TCP connection between Cloudflare and your origin is being reset during the SSL handshake causing the error.

Then, ask your hosting provider/system administrator to check if there are any server issues.

7. Note that Apache must configure 404 to log mod_ssl errors and nginx includes these errors in its standard error log, but it may  necessary to increase the log level.

8. Next, pause 203 Cloudflare or update your local hosts file to point directly at your server IP to test that your server is presenting a SSL certificate.

If you do not have a certificate install on your server you can generate one using our Origin CA 450 certificates.

9. If you cURL to the origin on port 443 and receive the error error:1408F10B:SSL routines:ssl3_get_record:wrong version number.

Disable TLS 1.3 on the Edge Certificates tab of the SSL/TLS app on the Cloudflare dashboard.

Then, to determine what TLS version is currently supported, use the following cURL command.

Then, replace MYORIGINIP with the IP address shown on the A record of your DNS app in the Cloudflare dashboard and www.example.com with your domain:

$ curl -svo /dev/null https://www.example.com --connect-to ::MYORIGINIP 2>&1 | egrep -v "^{.*$|^}.*$|^* http.*$"

10. Finally, test a specific TLS version by adding one of the following options to your cURL:

–tlsv1.0
–tlsv1.1
–tlsv1.2
–tlsv1.3

[Stuck in between? We’d be glad to assist you]

Conclusion

In short, today we saw steps followed by our Support Techs to resolve CloudFlare error 525 SSL handshake failed.