WebUI is an app that is installed on the CUBE to allow local control of the CUBE for skipping tracks, blocking tracks and artists, and changing "channels" (based on the channels you make available to the location)
Troubleshooting:
1. Make sure your computer or device is connected to the same network as the CUBE.
2. Confirm that the WebUI app is installed on that CUBE by going to cubemc.net, selecting that CUBE, and look for the "WebUI Settings" link.
If the link is not there, send a ticket to support@cubemc.com along with the CUBE serial number, and request that the app be added.
When a CUBE has WebUI installed, but is ONLY being used for On Hold messaging and music, as opposed to being used with a music service such as Revolution Music (revolutionmusic.info), this message will appear whenever a user visits the WebUI page:
"This CUBE does not have a music service yet"
This is normal behavior, and does NOT indicate that there is no On Hold Message or Music content assigned to the CUBE. Only that it is not being used for foreground or background music with a Licensed Music service.
Accessing the App
The WebUI app can be accessed by any computer or web-browsing device that is located on the same network as the CUBE. It is important to be on the same local network! A mobile device can access the CUBE by scanning the QR code on the back of the CUBE (a QR scanner is now built-in to the camera app of iOS devices...just open the camera, and point it at the QR code!)A computer can access the CUBE by going to my.cubemc.net. You will be prompted to enter the serial number and MAC address, which can be found on the back of the CUBE. Once you scan the QR code, or input the serial/mac, you will see the status of the player, and a round "play" button. Pushing the button will access the Control Center.

Access to the app can also be password protected to prevent unauthorized access. Passwords are set in cubemc.net. Simply go to the CUBE in question, click the WebUI Settings link, and set the password there.
When a CUBE has WebUI installed, but is ONLY being used for On Hold messaging and music, as opposed to being used with a music service such as Revolution Music (revolutionmusic.info), this message will appear whenever a user visits the WebUI page:
"This CUBE does not have a music service yet"
This is normal behavior, and does NOT indicate that there is no On Hold Message or Music content assigned to the CUBE. Only that it is not being used for foreground or background music with a Licensed Music service.
Using the App
The app gives the user control to select the Zone they want to control (if you have multiple Zones enabled: 
It also lets the user skip the current track, and block tracks and artists. Tracks or artists are only blocked on this location's playlists, and don't affect any other CUBEs. Blocked tracks or artists can only be unblocked by submitting a ticket to support@cubemc.com.

The user can also change "channels" (based on the channels you decide to make available to them):

(Simply click the name of the channel you want to change to. The "notes" icon will switch after a second or two to indicate which Channel is currently playing)
Related Articles
Adjusting the volume using a USB keyboard
Setting Master Output Volume The master volume of audio playback can be changed by temporarily plugging in a standard USB keyboard, and using the top two rows of keys (1 through 0, and Q through P). The row of keys 1 through 0 controls the Channel 1 ...
CUBE MOH Quickstart Guide
Welcome to CUBE! This Quickstart guide will help you get started using your CUBE and the CUBE CMS. To login: Go to cubemc.net. Login with: your email address Password: your password has been sent to you from CUBE, or you can request a password reset ...
LineIn function
The CUBE can be configured to play external audio through the CUBE, with the ability to fade out that content whenever messages are assigned to play. This would be useful if you are using a separate music source, rather than the Channels that are ...
Set a Static IP address via techmenu
Setting a static IP address via techmenu To set a static IP address on the CUBE using the techmenu, follow these steps: Connect a VGA screen to the VGA connection, and attach a USB keyboard to any USB port. Once you have a screen and keyboard ...
Asterisk or Freeswitch Configuration
For each on-hold program, we’ll supply a unique HTTP url, which is a live mp3 stream of the program. Within FreeSWITCH, this is handled by mod_shout. If you support playback of mp3 files elsewhere, mod_shout is probably already active in your ...