During installation of Grommunio from scratch on a Debian machine, the following error is being displayed during installation of the AAPI debian package:
/usr/lib/tmpfiles.d/grommunio-admin-api.conf:1: Failed to resolve group 'nginx'.
The problem will later cause a permission problem with NGINX. I wasn't able to figure this out myself, but my assumption is, that you were looking for user www-data instead of nginx, as this is the dedicated user for the web server on Debian.
