debian 11: amavis permissions
On amavis systems need to:
chgrp amavis /etc/amavis/conf.d/
chmod 750 /etc/amavis/conf.d/
chmod 644 /etc/amavis/conf.d/50-user
https://www.howtoforge.com/community/threads/bullseye-for-ispconfig.87450/page-2#post-427053