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Troubleshooting – 525 SSL Handshake error


Error 525 indicates that the SSL handshake between Cloudflare and the origin web server failed. This only occurs when the domain is using Cloudflare Full or Full (Strict) SSL mode. This is typically caused by a configuration issue in the origin web server, when this happens, you’ll see “Error 525: SSL handshake failed”

Quick Fix Ideas

  1. If you are a site visitor, report the problem to the site owner. Neither this Community nor Cloudflare Support can assist you. Cloudflare Support only works with the verified owner of the domain.
  2. Make sure you have a valid SSL certificate installed on your origin server.
  3. Check with your hosting provider to make sure they’re listening on port 443.
  4. Check to make sure your origin server is properly configured for SNI 1.2k.
  5. The cipher suites 289 that Cloudflare accepts 242 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. A cipher suite is a set of algorithms that help secure a network connection that uses Transport Layer Security (TLS) or its now-deprecated predecessor Secure Socket Layer (SSL). The set of algorithms that cipher suites usually include: a key exchange algorithm, a bulk encryption algorithm, and a message authentication code (MAC) algorithm.
  6. 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. Ask your hosting provider/system administrator to check if there are any server issues. Reviewing your webserver access/error logs would be a good place to locate this information.
  7. Note that Apache must be configured 279 to log mod_ssl errors and Nginx includes these errors in its standard error log, but it may be necessary to increase the log level.
  8. Pause 110 Cloudflare or update your local hosts file to point directly at your server IP to test that your server is presenting an SSL certificate. If you do not have a certificate installed on your server you can generate one using our Origin CA 275 certificates. This is a free certificate for the purpose of encrypting the connection between Cloudflare and your web server so that you do not need to purchase a certificate.
  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.