The device does not connect to a wireless network with hidden SSID.
An option in the devices' network configuration is missing.
The GEL Universal Desktop Linux v5 manual describes in detail how to connect to a hidden wireless network.
For older versions such as Universal Desktop Linux 4.12.100, 5.01.100 and 1.06.100 (SoC):
- Start local IGEL Setup or open device configuration in UMS
- Go to Network > LAN Interfaces > Wireless > Authentication > WPA Encryption
- Set parameter AP Scan Mode = no broadcast
- Save your settings