Some problems with restarting unbound service

[pijack]

Hi,

I installed pihole + unbound on a linux container in Proxmox. It works great. I then tried to upgrade it with DoH, and it seemed to be as simple as this guy said in a video here:

How to safely surf the internet using Pi-Hole, Cloudflare & Unbound

So I stopped the unbound service and added these lines at the end of the pi-hole.conf file:

...
#Enable DNS over TLS with Unbound and Cloudflare

    tls-cert-bundle: /etc/ssl/certs/ca-certificates.crt
    forward-zone:
    name: "."
    forward-tls-upstream: yes
# Cloudflare DNS
    forward-addr: 2606:4700:4700::1111@853#cloudflare-dns.com
    forward-addr: 1.1.1.1@853#cloudflare-dns.com
    forward-addr: 2606:4700:4700::1001@853#cloudflare-dns.com
    forward-addr: 1.0.0.1@853#cloudflare-dns.com

BUT, when I try to restart the service I got this error message:

root@pihole:~# service unbound start
Job for unbound.service failed because the control process exited with error code.
See "systemctl status unbound.service" and "journalctl -xe" for details.

systemctl status unbound.service says:

* unbound.service - Unbound DNS server
   Loaded: loaded (/lib/systemd/system/unbound.service; enabled; vendor preset: enabl
   Active: failed (Result: exit-code) since Sat 2021-10-16 16:53:30 UTC; 7min ago
     Docs: man:unbound(8)
  Process: 1017 ExecStart=/usr/sbin/unbound -d $DAEMON_OPTS (code=exited, status=1/FA
  Process: 1014 ExecStartPre=/usr/lib/unbound/package-helper root_trust_anchor_update
  Process: 1011 ExecStartPre=/usr/lib/unbound/package-helper chroot_setup (code=exite
 Main PID: 1017 (code=exited, status=1/FAILURE)

Oct 16 16:53:30 pihole systemd[1]: unbound.service: Main process exited, code=exited,
Oct 16 16:53:30 pihole systemd[1]: unbound.service: Failed with result 'exit-code'.
Oct 16 16:53:30 pihole systemd[1]: Failed to start Unbound DNS server.
Oct 16 16:53:30 pihole systemd[1]: unbound.service: Service hold-off time over, sched
Oct 16 16:53:30 pihole systemd[1]: unbound.service: Scheduled restart job, restart co
Oct 16 16:53:30 pihole systemd[1]: Stopped Unbound DNS server.
Oct 16 16:53:30 pihole systemd[1]: unbound.service: Start request repeated too quickl
Oct 16 16:53:30 pihole systemd[1]: unbound.service: Failed with result 'exit-code'.
Oct 16 16:53:30 pihole systemd[1]: Failed to start Unbound DNS server.

e poi journalctl -xe:

root@pihole:~# journalctl -xe

-- Automatic restarting of the unit unbound.service has been scheduled, as the result
-- the configured Restart= setting for the unit.
Oct 16 16:53:30 pihole systemd[1]: Stopped Unbound DNS server.
-- Subject: Unit unbound.service has finished shutting down
-- Defined-By: systemd
-- Support: http://www.ubuntu.com/support
--
-- Unit unbound.service has finished shutting down.
Oct 16 16:53:30 pihole systemd[1]: unbound.service: Start request repeated too quickl
Oct 16 16:53:30 pihole systemd[1]: unbound.service: Failed with result 'exit-code'.
Oct 16 16:53:30 pihole systemd[1]: Failed to start Unbound DNS server.
-- Subject: Unit unbound.service has failed
-- Defined-By: systemd
-- Support: http://www.ubuntu.com/support
--
-- Unit unbound.service has failed.
--
-- The result is RESULT.
Oct 16 16:55:40 pihole systemd-networkd[61]: eth0: Configured
Oct 16 17:00:01 pihole CRON[1842]: pam_unix(cron:session): session opened for user ro
Oct 16 17:00:01 pihole CRON[1843]: (root) CMD (   PATH="$PATH:/usr/sbin:/usr/local/bi
Oct 16 17:00:01 pihole CRON[1842]: pam_unix(cron:session): session closed for user ro
Oct 16 17:00:39 pihole systemd-networkd[61]: eth0: Configured

I know that some people say that it is not the right way to use Unbound or DoT with Cloudflare, but it is not my point here.
I'm trying to understand why the unbound service doesn't get started anymore.
Could you help me with this please? Thanks