I just got this yesterday. I owned the first Galaxy watch a few years back and it fizzled not long after a year. Even still, I decided to buy another one: the Galaxy Watch 46 mm. Although the auto wake-up feature DID work for the first 6 hours, it clearly isn't working now. I've tried turning the feature off and back on several times to no avail. I've also rebooted the watch which didn't help either. Any suggestions?
Figured it out: The Do Not Disturb setting was on. Once I turned it off, the problem was solved.
When I originally set the watch up with my Samsung phone, there was a question as to whether I wanted to follow the Do Not Disturb setting from my phone -- I said yes. My phone has Do Not Disturb set from 11 pm to 7 am. So, I'll have to see if that is honored now that I have turned the watch setting off.