Migration partielle vers Stretch / Yunohost 3.x

J’ai essayé de dépanner le pb fail2ban en m’inspirant de Fail2ban : impossible de démarrer le service (failed) - #16 by AntoineC
Mais cela n’a pas marché.

apt-cache policy fail2ban
systemctl stop fail2ban
mv /etc/fail2ban /etc/fail2ban.old.2020.12.28
wget http://ftp.fr.debian.org/debian/pool/main/f/fail2ban/fail2ban_0.9.6-2_all.deb
dpkg -i --force-confmiss fail2ban_0.9.6-2_all.deb
dpkg -i --force-confmiss /var/cache/apt/archives/fail2ban*.deb

OK
Mais pb sur :

yunohost service regen-conf fail2ban --force

root@YunoHost:~# yunohost service regen-conf fail2ban --force
Success! The configuration has been updated for service 'fail2ban'
Warning: Job for fail2ban.service failed because the control process exited with error code.
Warning: See "systemctl status fail2ban.service" and "journalctl -xe" for details.
Error: 5
fail2ban: 
  applied: 
    /etc/fail2ban/filter.d/yunohost.conf: 
      status: force-created
    /etc/fail2ban/jail.conf: 
      status: force-updated
  pending: