Content Security Policy: The settings of the page have blocked the loading of a resource ("script-src")

CSP? Well, I have already passed my Apache2 Conf… As well as the expose part of the app.yml

Why are you exposing this? Your localhost uses port 90.

Because i have to choose a different port for https than for http?

You don’t use SSL between reverse proxy and backend. Reverse proxy has terminated SSL because it is the wall between outside world and backend.

Works! But now I have this error:

Job exception: SSL_connect returned=1 errno=0 peeraddr=<my_ip>:587 state=error: certificate verify failed (unable to get local issuer certificate)

Are you trying to get or handle certificate on Discourse side? That sounds like error from Ruby. If so, then don’t.

You have to comment out these if already aren’t:

# - "templates/web.ssl.template.yml"
# - "templates/web.letsencrypt.ssl.template.yml"

This is in my postfix

Then you are on wrong forum. But you should check your cinfiguration of postfix, firewall etc.