I am facing the exact same issue.
When I unplug the device for some hours I can recover it holding the button for 10 secs many times. Luckily I then get into repairing mode and I can bring the gateway back online. But I have to repair all devices and then (can’t figure out when) suddenly I run into the issue again.
I have the feeling that the power contact inside is not stable as I get some strange short electric flickering sound inside.
Anyone else facing such problems? Right now I can’t gat the gateway working at all