I did a new install of debian and find that exim and spamassassin are not recognized services. That is, in /etc/systemd/system/ exim and spanassassin are not listed.
So when I do # systemctl start exim.service RROR:systemctl:Unit exim.service could not be found. This no help: # systemctl enable exim.service ERROR:systemctl:Unit exim.service could not be found. # systemctl start exim ERROR:systemctl:Unit exim.service could not be found. Why are exim and spamassassin automatically present as services? -- Haines Brown