The Light sensor
The bridge is equipped with a light sensor above where the micro usb power cord plugs in. In the current version of firmware (1.05) the LED light ring is programmed to dim and turn off if its surrounding are dark. This works in a similar way to how the screen on your phone automatically dims. This feature allows you to place the bridge anywhere in your home including bedrooms with out disturbing someone that may be sleeping in that room. When the light on your bridge is off because of dark surroundings it will operate and control your blinds normally.
Check the power supply
If the bridge doesn't seem to be working it is always good practice to make sure that it is receiving power. Try powering the bridge with a different outlet. Try using a different power supply and any other micro usb cord.
Stuck in Boot-loader mode
If the light on your bridge is off in broad daylight and you are certain that the bridge is receiving power it may be stuck in boot-loader mode. This will typically happen only after an unsuccessful firmware update attempt. When your bridge is in this state it will not function at all. It will appear as if it is totally dead. If this has happened to your bridge there is no need to worry, as there are a few simple steps that you can take in the MySmartBlinds app on an iOS device to get it out of this state.
Getting your bridge out of boot-loader mode
Step 1: Open the MySmartBlinds app on an iOS device*
Step 2: Tap the menu in the top left corner, then tap bridge
Step 3: Tap and Hold the "?" icon in the top right corner of the screen
This will open up a screen where the app will search for your bridge and force it out of that state. Once your phone finds the bridge your bridge will light up and once again be usable.
*this procedure has not yet been added to the Android app.