If you are using AC power, check the outlet and verify that your DreamStation Go is properly plugged in and there is power to the outlet. Make sure the AC power cord is connected correctly to the device's power inlet.
If you are using a battery pack, make sure the battery pack is securely connected to your DreamStation Go. If the battery pack has been exposed to extreme temperatures, allow the battery pack to cool or warm to room temperature. Check to see if your battery pack needs to be charged or replaced.