After many years of flawless operation, my watch switched off after briefly showing a message on an update (don't know the exact message) and does not turn back on. I have tried holding the power button for 15s, 30s and even for more than a minute. I tried the same with the back button and both buttons at the same time, but there is no response at all (nothing on the screen and no vibration or anything). I have also tried charging it with an adapter and laptop, and also a different cable. The charging contacts all look fine (no debris etc.).
Any idea on how I can turn my watch back on?