When trying to connect to Unify Network Controller interface, it was not responding.
Checking the port with netstat showed the service was not started but service unify status
reported the contrary.
Device: RPi 3 with 16gb storage
java JDK not up to date on latest raspbian image for a long time
Replace Oracle JDK by openjdk, it worked great!
sudo apt-get install openjdk-8-jre-headless -y
then restart the service: sudo service unify restart