The thing is that it was working without any issue until it randomly stopped working today. I’ve already checked nginx config files, generated new ssl certs and everything but still having the same issue.
If HTTPS doesn’t work when the proxy is disabled, it means your server is misconfigured in some way. You should keep the proxy disabled until it works.
If you disabled the proxy, I could probably tell you where the problem lies as well.
It would, just with a warning that the site is unsafe.
But you don’t even get to that warning, the webserver does not respond with any certificate at all. This means the webserver is misconfigured in some way.
* TLSv1.0 (OUT), TLS header, Certificate Status (22):
* TLSv1.3 (OUT), TLS handshake, Client hello (1):
* OpenSSL SSL_connect: Connection reset by peer in connection to panel.cubicservers.de:443