Ubiquiti - Troubleshooting - Controller Offline

Cloud Key Gen 1 and Gen 2 (firmware 1.x) and software installs will show up in https://network.unifi.ui.com

Cloud Key Gen 2 (firmware 2.x) and Dream Machines will show up in https://unifi.ui.com

NOTE: The following is required for the Controller to show up in one of the above URL.

It needs to be on and running.
Remote Access needs to be enabled.
Outbound firewall rules need to allow access outbound for the controller to reach to the portals.

References