Problem to back up docker volumes

Hi,

I know it is a bit off topic, but I have a problem to back up my docker
volumes (.../docker/volumes):

sudo -u amanda amcheck -c normal puffer1000

Amanda Backup Client Hosts Check
--------------------------------
ERROR: puffer1000: [puffer1000: Could not access /home2/docker/volumes
(/home2/docker/volumes): Perm
ission denied]

I suspect it is something to do with some access control list on Linux
(I am more used to FreeBSD); I checked but saw nothing glaring to my
face:

on@puffer:~$ sudo getfacl /home2/docker/volumes
[sudo] password for on:
getfacl: Removing leading '/' from absolute path names
# file: home2/docker/volumes
# owner: root
# group: root
user::rwx
group::---
other::--x

I even tried to create a test directory, I gave it the same ACL and
could amcheck and amdump that test directory.

I must say that I am at lost here on what could be the main cause for
this issue. and idea or pointer will be very welcome.

TIA,

Olivier
--