Postfix as "normal" daemon under 18.04?

[Tom H]

On Tue, Feb 9, 2021 at 6:46 PM Robert Heller <heller at deepsoft.com>
wrote:
>
> How do I get Postfix to run as a "normal" daemon under Ubuntu
> 18.04?
>
> I installed postfix on a Ubuntu 18.04 server and copied a batch of
> config files from a CentOS 6 system. But postfix under Ubuntu
> 18.04 is weird. The main postfix service file
> (/lib/systemd/system/postfix.service) does not actually start the
> daemon (like it does with a CentOS 7 system), instead there is a
> /lib/systemd/system/postfix at .service file, that gets called to
> create instances. What is going on here?  Is there some strange
> and exotic magic involved?  Is it not possible to just run postfix
> as a regular daemon?

Ubuntu has both
/lib/systemd/system/postfix.service
and
/lib/systemd/system/postfix at .service

The former's enabled and started by default when you install postfix.
Check your logs for errors.