What is the error you are seeing. 500 error or any other.
Can you check the log when you try to login to the webpage.
[gitlab@stages ~]$ gitlab-ctl tail production
[gitlab@stages ~]$ gitlab-ctl tail ngnix
[gitlab@stages ~]$ cd /var/opt/gitlab/logs/
[gitlab@stages ~]$ cd ngninx/
[gitlab@stages ~]$ cd gitlab-rails
Have you enabled HTTPS?
Created any self signed certificates ?
Do you see any error (in red) in reconfigure command.
Is it possible for you to connect to the server in which Gitlab is installed via VNC view and open a browser and verify if it is accessible from the same machine bit not from other machines.