Remote access to gitlab hosted on my company's server

Good morning all !!
I installed gitlab-ce on my company server which is a debian version 9 linux server.
In the configuration of gitlab I entered the domain name for remote access to gitlab. This one does not work.
My company’s server hosts multiple websites so I had to use apache and nginx in my setup.
When I enter the dns of my redirection to the gitlab server, the url sends me to one of the company’s site.
I checked the configuration of Apache and I even clone the server and delete all the configuration files of the other sites in “sites-available” leaving only the gitlab conf file.
Ditto the dns refers me to one of the sites of the company even having reconfigured “gitlab-ctl reconfigure” and entered the command “systemctl reload apache2” I do not see where my problem is and I am running out of ideas in my research.

gitlab is meant to be installed on it’s own server, since nginx will conflict with apache ports 80 and 443. Chances are all your problems are because of this unless you made sure to bind nginx to one IP address and apache to a different ip address. As they cannot bind to the same one.

The problem of it going to your website is because Apache answers it and not nginx, and therefore since it doesn’t find the hostname, it finds a VHOST and displays that instead.

If you did have multiple IP addresses on the server, and DNS was redirected accordingly then it would work fine. I know, because I have a server that works exactly like this and works fine. So your conflict is because of this.

But to help further, we need to know much more configuration about your server, what services running, what are listening or not listening (maybe nginx didn’t start because of conflict). Also output of gitlab-ctl status will help.

Thank you for your reply.
Linux version: Debian 9
Indeed Apache and Nginx are installed on the server at first I had deactivated the Nginx server to “false” in the gitlab.rb file but without results I then reactivated it thinking that the bad display of the pages came from there .

The server hosts 3 websites each on a different dns in the configuration of apache, plus a vhost assigned to gitlab.

Here is the gitlab vhost:

  ServerName www.gitlabcd.com
  ServerSignature Off

  ProxyPreserveHost On

  <Location />
    Order allow, deny
    allow from all

    ProxyPassReverse http://127.0.0.1:8080
    ProxyPassReverse http://www.gitlabcd.com
  </Location>

  RewriteEngine on
  RewriteCond% {DOCUMENT_ROOT} /% {REQUEST_FILENAME}! -F
  RewriteRule /→-\/\w\. Danemark+\.git\/ http://127.0.0.1:8282% DanemarkREQUEST_URI} [P, QSA, L]
  RequestHeader set X-Forwarded-port "80"

  # needed for downloading attachments
  DocumentRoot / opt / gitlab / embedded / service / gitlab-rails / public

```</VirtualHost>


the IP address of the server is the same for each site the redirection is carried out at the level of vhost and DNS.
I also use let'sencrypt for the site certificates as well as for the gitlab certificate.
I did the installation of gitlab from this source: https://opensharing.fr/gitlabce-installation-serveur
I did not follow the installation identically but the current server configuratio is close to this one.

In your message you tell me about assigning several Ip addresses to each DNS: isn't this what is already in place with respect to vhost? and otherwise how to do?

Here is the return from gitlab-ctl start:![gitlab-ctl start|389x292](upload://yOFJ82NZDA3kGe6hbnREJU2zTvC.png) 

thank you in advance for your help