When trying to start Amavis you see this in the mail log:
Oct 02 03:20:15 condor3648 systemd[1]: Starting LSB: Starts amavisd-new mailfilter...
Oct 02 03:20:16 condor3648 amavis[1697]: starting. /usr/sbin/amavisd-new at condor3648.startdedicated.com amavisd-new-2.11.0 (20160426), Unicode aware, LC_ALL="C", LANG="en_US.UTF-8"
Oct 02 03:20:16 condor3648 amavis[1705]: (!)Net::Server: 2020/10/02-03:20:16 Can't connect to TCP port 10024 on 127.0.0.0 [Address already in use]\n at line 68 in file /usr/share/perl5/vendor_perl/Net/Server/Proto/TCP.pm
Oct 02 03:20:16 condor3648 amavis[1690]: Starting amavisd: amavisd-new.
Oct 02 03:20:16 condor3648 systemd[1]: Started LSB: Starts amavisd-new mailfilter.
Try killing any stuck amavis and amavisd-milter processes:
pkill -u amavis
Now restart amavis and Amavisd-milter:
Centos/RHEL/CloudLinux/AlmaLinux
systemctl restart amavisd
systemctl restart amavisd-milter
Debian/Ubuntu
systemctl restart amavis
systemctl restart amavisd-milter