Install amavisd-milter by entering the following commands in the terminal:
sudo apt update sudo apt install amavisd-milter
amavisd-new interface for milter-capable MTAs
This package provides a milter for amavisd-new that works with Sendmail or Postfix, using the AM.PDP protocol. . Replacing the older amavisd-new-milter program, amavisd-milter makes use of the full functionality of amavisd-new. It supports using spam and virus information header fields, rewriting message subjects, adding address extensions, and selectively removing recipients.