I'm attemping to install nxlog on a fresh Ubuntu 16.04 machine from nxlog-ce_2.9.1716_ubuntu_1604_amd64.deb. It seems to install correctly, however I get an error from the post-installation script.

Relevant output from 'dpkg -i nxlog-ce_2.9.1716_ubuntu_1604_amd64.deb':

Preparing to unpack nxlog-ce_2.9.1716_ubuntu_1604_amd64.deb ...
Unpacking nxlog-ce (2.9.1716) ...
Setting up nxlog-ce (2.9.1716) ...
[....] Starting nxlog (via systemctl): nxlog.serviceFailed to start nxlog.service: Unit nxlog.service not found.
 failed!
dpkg: error processing package nxlog-ce (--install):
 subprocess installed post-installation script returned error exit status 5

Running the dpkg command again, or just ignoring that it "failed" and running '/etc/init.d/nxlog start' afterwards both are successful.

Any idea why this is happening?

The dpkg command returning an error status is causing issues when performing the installation via an automation script.