borg (not borg server) updated to testing, and still the same error :
~ sudo systemctl start borg.service
~ sudo systemctl status --lines 100 borg.service
● borg.service - Run backup borg
Loaded: loaded (/etc/systemd/system/borg.service; enabled; vendor preset: enabled)
Active: failed (Result: exit-code) since Fri 2020-07-31 11:22:29 CEST; 3min 8s ago
Process: 4225 ExecStart=/usr/local/bin/backup-with-borg (code=exited, status=1/FAILURE)
Main PID: 4225 (code=exited, status=1/FAILURE)
juil. 31 11:18:53 myserver.fr backup-with-borg[4225]: [########++++........] > Backing up database...
juil. 31 11:18:53 myserver.fr sudo[8474]: root : TTY=unknown ; PWD=/home/yunohost.backup/tmp/auto_kresus/apps/kresus/backup ; USER=postgres ; COMMAND=/bin/bash -
juil. 31 11:18:53 myserver.fr sudo[8474]: pam_unix(sudo:session): session opened for user postgres by (uid=0)
juil. 31 11:18:54 myserver.fr sudo[8474]: pam_unix(sudo:session): session closed for user postgres
juil. 31 11:18:54 myserver.fr backup-with-borg[4225]: [############++++....] > Backing up systemd service...
juil. 31 11:18:56 myserver.fr backup-with-borg[4225]: Création d’une archive de sauvegarde à partir des fichiers collectés …
juil. 31 11:19:02 myserver.fr backup-with-borg[4225]: Échec de l’exécution du script : /etc/yunohost/hooks.d/backup_method/05-borg_app
juil. 31 11:19:02 myserver.fr backup-with-borg[4225]: Échec de la méthode de sauvegarde personnalisée à l’étape 'backup'
[etc… for all services]