Dlux is only opened for localhost by default. You can change this behaviour by installing odl-aaa-cli and run:

aaa:change-user-pwd -user admin

To get DLUX listenning everywhere:

#Debian Like distros
iptables -I INPUT 1 -p tcp -m tcp --dport 8181 -m conntrack --ctstate NEW -j ACCEPT #authorize DLUX
iptables-save > /etc/iptables.save

#RED HAT like distros
firewall-cmd --zone=trusted --change-interface=eth0

If login interface does not show. It is because you probably can't reach internet. You need to download some dependencies which means you can't be only behind a http proxy.