NCP Restore not working after failed Nextcloud update to 27.1.1

I recently upgraded my Nextcloud install to the latest version 27.1.1 and now my whole install is deleted and It’s asking me to make a new admin account. I tried to restore my install with a backup that was made automatically when I updated, but the restore is not working properly. It always gets stuck at “Check free space”. Can someone help me?

As the message indicates, can you please check the disk-space?
To get a complete picture you can use
sudo ncp-report

i had a similar problem, in my case there was an incomplete backup remaining in /var/www/nextcloud/ which normally gets moved to a different directory for upgrade backups, but when the upgrade fails it probably does not happen and cloggs your sd-card