What type of hardware are you using: VPS bought online
What YunoHost version are you running: 12.1.39 (stable)
How are you able to access your server: The webadmin
SSH
Are you in a special context or did you perform specific tweaking on your YunoHost instance ?: no
Describe your issue
The system sends email alerts about [borg] & when upgrading Nextcloud there is essentially the same error.
Aborting the upgrade, because a safety backup could not be created (Command ‘[‘du’, ‘-sb’, ‘/var/www/nextcloud’]’ returned non-zero exit status 1.)
This command indeed fails when invoked by Yunohost admin without sudo , but with that it runs as intended.
Borg reports about the failures on a few apps. Not a tiny one (like Borg itself) among those, also the system backups goes through each time.
Before creating this topic I went over https://forum.yunohost.org/t/cant-backup-nextcloud-anymore-since-14-days-wheter-on-gui-borg-nor-cli/40729/22: though the command failing is the same, sudo behavior is different too much (and that topic does not really have a solution anyway).
Share relevant logs or error messages
Aborting the upgrade, because a safety backup could not be created (Command ‘[‘du’, ‘-sb’, ‘/var/www/nextcloud’]’ returned non-zero exit status 1.)