Hi, I am encountering the same blank screen
I have a Vertical Solar Titanium, brand new, 1.5 months old, never had encountered any issue at all.
During a snorkelling session, very soft, the watch started to glitch and became more and more unresponsive, first the central button was not working, then the upper, then I tried to reboot it by keeping pressed the button, and it went off completely. Now it is “dead” with no signs of life.
Nothing is happening even if connected to the charger, the 12 seconds don’t do a thing.
I have been suggested by the support to hold the upper button for 60 secs while charging, with no luck.
Do you have any more suggestions, except to send it in Finland to check it? It must be software related, the hardware is almost perfect.