guides and articles about photo booths.
Dzentech
MIXUP

MixUp troubleshooting: Backlight

Try to unplug the booth and plug it back. 
If you still can't connect to the backlight from MixUp app, then turn off the Bluetooth on your laptop and turn it on again.
In MixUp app - settings check that the backlight is turned on and brightness is more than 0. 
There are 2 options: for the StandBy mode and for the Shooting mode. In the settings screen, you'll only be able to see the Standby brightness.
If you still can't connect to the backlight, then please restart the laptop.
Text us if it doesn't help.