This might indicate that the on-board CPU has not booted yet. Please check if the CPU button light is BLUE. If not, power on the CPU manually by pressing the CPU button once. The CPU button light should then turn blue. If the CPU will not turn on ...
In most cases, this will be caused by a wrongly formatted SD card which results in the unit not recognizing the SD card at all. All SD cards need to be formatted in the EXFAT file system in order for the unit to detect the card.