I have installed Gitlab through omnibus installation with existing NGINX installation. I was following the docs guide, installed Passenger using this guide (it also updated my installed nginx): https://www.phusionpassenger.com/library/install/nginx/install/oss/xenial/
Also i've updated /etc/gitlab/gitlab.rb to following settings:
external_url 'http://git.domain.kz'
nginx['enable'] = false
Here's the output of command sudo gitlab-ctl tail