Install amavisd-new-postfix by entering the following commands in the terminal:
sudo apt update sudo apt install amavisd-new-postfix
part of Ubuntu mail stack provided by Ubuntu server team
AMaViSd-new is a script that interfaces a mail transport agent (MTA) with zero or more virus scanners, and spamassassin (optional). . It supports all common virus scanners (more than 20 different AVs), with direct talk-to-daemon support for ClamAV, OpenAntiVirus, Trophie, AVG, f-prot, and Sophos AVs. . AMaViSd-new supports all MTAs through its generic SMTP/LMTP filter mode (ideal for postfix and exim). It is faster and safer to use the SMTP/LMTP filter mode than using the AMaViS pipe client. It supports sendmail milter through this package. . This package contains configuration files for amavis and alters postfix configuration to utilize amavisd-new.