I have this exact same clock. Are you positive it’s not going off? You may have it set to be quiet in the beginning and ramp up to being loud over 15-30 minutes which is supposed to wake you up gradually. So perhaps you only noticed it going off at 10:46.
For instance, I want to be awake at 7, so I set mine for 6:30 with a 30min gradual wake up (sounds and light gradually go up for 30 min).
That setting is not required and you can have it just wake you up, but then it defeats the point of a sunlight alarm in my opinion.
As someone else mentioned, you probably hit snooze without realizing it while still mostly asleep. Snooze is 9 minutes. On this clock, the “snooze button” is literally the entire face of the clock. When the noise initially went off, if you rolled over and tapped the clock it would have reset the alarm.