Which model watch is this? Normally, you can hold down the light button for about 20 seconds (top/left) until it goes off (screen turns black). Then power it on again by holding the light button again for 2 seconds.
Thank you. This worked for me. For others who have this problem, you really have to hold down the light button quite a while for the screen to turn off = black. I think it’s even longer than 20 seconds but this does work.