That seems like a very bad idea. We generally don’t use a “root” account at all on Ubuntu. You should use
sudo, which temporarily gives you root privilege without needing a root account. I don’t think you can blame GitLab here.
You haven’t said how you installed Gitlab (there are at least three ways I know of: omnibus, source, and docker), so it’s not possible to know what has broken things.
Your current error messages are saying that you are trying to login via SSH as
root. That is generally forbidden. It can be overridden, but I’m not going to help you shoot yourself in the foot by digging up the method (which I haven’t needed in 20+ years of administering Linux systems). Login as yourself, then use
sudo. I don’t think those messages are related to the systemd error starting Apache, but they could be.
You say “my system is down”, but only show us a system that’s up. Do you really mean that Apache is down? Then login as yourself–that is, the user who initially installed Ubuntu, or another user who is either in the
sudo group or the /etc/sudoers file–and try to restart Apache with:
sudo systemctl restart httpd
And another thing…
httpd is not the name of the standard Ubuntu Apache daemon (the Ubuntu service has been
apache2.service for as long as Ubuntu has used systemd, and the daemon has been
apache2 since they stopped shipping version 1.X), so not only don’t we know how you installed GitLab, we don’t know how you installed Apache, either.