AB Gaetewaynot starting

After updating the firmware,via OATm the gateway is not starting : no LED on the back, it s not reconized by Config Tool…what should I do?
Serial number is B4E62DBE985D

I tried factory reset but it didn’t help. When I power the device, I have the screen light next to LAN cable, but it never turn yellow after I plugged the LAN cabled.
What should I do please?

Did you do OTA first? Try to factory reset again.

Please record a video for the LAN LED when it’s starting