Comment 2 for bug 1696612

From the log:
The value of variable $myhostname ...en
a fully qualified domain name; per...h.
You must explicitly assign a FQDN ...me
in /etc/amavis/conf.d/05-node_id, ...'s
network name!

This is a bit shortened, but you can see it again in full size with :
 $ systemctl status amavis.service

Long story short, the service is not properly configured and fails to start.
Due to that an upgrade fails as it needs to restart the service,