Getting Access Denied Error when Using systemctl as root

 I got this error in one of our server, when trying to restart nginx

# systemctl status nginx

Failed to get properties: Access denied

Does not make sense, I am a root user. After some searching, a few suggestions came. 

The first suggestion was to restart systemctl daemon:

# systemctl daemon-reexec

That did not work for me. Another solution is to disable selinux temporarily, but this also did not work for me:

# setenforce 0 

The last thing that I tried (that actually worked) was to sending sigterm to systemd, and it will restart by itself:

# kill -TERM 1

If you guys happened to encounter this sort of error, you can try all the above. Some might suit you better than the other.