How to fix "This site cannot provide a secure connection"?

Question

Nginx

This error occurs on Iphone with IOS version 14+ (on version 13.4 everything works without problems):



A little background: There is a site that is located on the subdomain: subdomain.example.com

CloudFlare is connected to the domain with a DNS CNAME record with the content example.com and named subdomain

In other words, requests from the subdomain go to the main domain and are already processed by the web server there. In the CloudFlare settings, Tls 1.3 support is enabled, free SSL is connected, and the "Flexible" mode is set. On other platforms (Windows, MacOS, Linux, Android) everything works without problems. I understand the matter in the IOS security policy, which, for some reason, cannot establish a secure connection. Maybe the fact is that SSL is in fact issued in the name of Cloudflare, and not on the example.com domain?

Answer 1

Maybe the fact is that SSL is in fact issued in the name of Cloudflare, and not on the example.com domain?

The certificate must be issued in the name that you have painted over in red. Nothing is clear from the screenshots, check the domain at https://www.ssllabs.com/ssltest/analyze.html , for example.

Answer 2

look at the headers in the browser, there clearly slips either a redirect or a POST of some kind without SSL