Also, not directly related to your question, I noticed that the IP address or host seems to change regularly. I think that's the problem why the share is always offline after some time:Hello.
Did you use the right username and share name?
The username is likeuXXX-sub1
The share name is the same as the username, not the name of the shared folder!uXXX.your-storagebox.de/uXXX-sub1
Code:
ls: cannot access '/mnt/pve/hetzner-box': Host is down
I remount it now daily with a cron job, I hope that helps...