certbot.errors.AuthorizationError: Some challenges have failed

Your domain doesn’t answer - https://check-your-website.server-daten.de/?q=projo.ocus.com

Domainname Http-Status redirect Sec. G
http://projo.ocus.com/
157.230.115.5 -2 1.076 V
ConnectFailure - Unable to connect to the remote server
https://projo.ocus.com/
157.230.115.5 -2 1.077 V
ConnectFailure - Unable to connect to the remote server
http://projo.ocus.com/.well-known/acme-challenge/check-your-website-dot-server-daten-dot-de
157.230.115.5 -2 1.094 V
ConnectFailure - Unable to connect to the remote server

Creating a Letsencrypt certificate via http validation: A working port 80 webserver is required.

Works it internal? If yes, there may be a firewall or another blocking instance.