Where can I check the docker images? 'docker' doesn't exist in my /var/lib/

That's weird.
In 'graphs' I see under 'Disk usage' that I use 55GB...

Nextcloud is only 10,8 GB at the moment (deleted files deleted).

Deleted some big files so it keeps running normal now... still Nextcloud indicates a hd of 20GB, Digitalocean says 60GB...

Hello,

My mail + Nextcloud are going offline all the time.

Logs say it has to do with full storage... Nextcloud (after restarting running again for a short time) indicates also a full storage... BUT I have +20GB free space on the Digital Ocean droplet...

What can I do?
Hope someone can help