Hereby a slightly optimized version of the workaround suggested by Andreas:
1. create the missing symlink:
$ ln -s /usr/lib/systemd/user/fetchmail.service /etc/systemd/system/
2. Edit the service by creating a drop-in file:
$ systemctl edit fetchmail.service
And place the following content at the top of the file (and save it):
[Service]
# Run this service as user fetchmail.
#
User=fetchmail
# The ExecStart setting is parsed as a list. Hence, first clear the list
before adding the new entry.
ExecStart=
# Now add the new entry.
ExecStart=fetchmail --nodetach --daemon 300 -f /etc/fetchmailrc
3. Optional -- only needed if you changed ownership of
file /etc/fetchmailrc as suggested by Andreas:
$ chown fetchmail:root /etc/fetchmailrc
4. Restart the service:
$ systemctl restart fetchmail.service
5. Verify that the service started correctly:
$ systemctl status fetchmail.service
