Last night my Fenix 8 went blank and I was unable to restart it. The battery was fully charged. I tried an hard reset but nothing happened. I plugged the watch into my mac and it booted up and was seen by Garmin Express, but once I unplugged the watch switched off. I also found that the watch would boot up when plugged in. While the watch was plugged in I tried a settings full reset but as soon as the charge cable was removed the watch it went blank again and would not respond.