So your let’encrypt certificates aren’t correctly set in nginx configuration files. I don’t know much CloudFlare so I can’t help you further
Look also with these commands « systemctl status nginx.service » and « journalctl -xe » as indicated.
I guess you use certbot to get let’s encrypt certificate, isn’t it ?
So, check first if any error occurred in the file /var/log/letsencrypt/letsencrypt.log.
Remember that, by default, certbot uses a simple http connection to your server to validate the certificate’s transaction. So you need to have your web server (clearly your virtual host) listening on port 80 (and that port to be opened in the firewall system).
Is there a command line syntax I can use to do this? I am a marketing guy by trade, not a software engineer. I would be happy to send some beer money via PayPal to help me with this - it would be my pleasure actually.