Hello,
I no very little about this, so please be kind. Our webpage is secured with valid SSL certificate, but Chrome flags us as unsafe. No mixed content that I could find.
I’m running a WordPress site (rediens.cz) with a valid SSL certificate (RSA 4096 bits, issued by R12, valid until Nov 2025).
According to SSL Labs (SSL Server Test: rediens.cz (Powered by Qualys SSL Labs)), it is rated A-, with HSTS enabled, TLS 1.2 support, and forward secrecy.
I use Elementor, Really Simple Security, W3 Total Cache and Wordfence plugins.
I know I'm late, but www is a subdomain. You shouldn't need to direct to it in order to have valid SSL.
In WordPress, go to Dashboard > Settings > General. WordPress Address (URL) and Site Address (URL) should both have https, not http regardless of whether you're using www or not.
Possible issues:
You might have only requested one SSL certificate for www.rediens.cz. If you want an SSL certificate for rediens.cz, you need to request a second certificate for it.
Your HTTP server isn't able to use the certificate for some reason. Do you have access to your server? If so, do you know whether you're using Apache, NGINX, HAProxy, or something else?