Serverinfo says: Freespace: -2 B

In my Nextcloud installation (version 16) on a shared host (STRATO) I cannot upload anything via web interface. Error is: Not enough disk space. The Nextcloud serverinfo says: -2 B free… There is for sure enough free space left…

Any advice?

Goto Settings > User and check the quota of the user. I remember that a user had once mixed-up the unit behind the configured value so that the quota was lower than the already used disk space which caused the mentioned error message.

I am using the admin without quota.