I think I found the problem/solution (at least it seems to be working for me). For some reason on the notifications seems to not be allowed when on do-not-disturb mode (although I clearly specify alarms).
The way I fixed it is to go to the notification preferences of the clock app and change them to override do-not-disturb. App info -> Notifications -> Alarm and timer alerts -> Ignore Do not Disturb (change it to on)
I hope it helps.
Apparently my solution worked for a couple of times (when testing) but then it stopped again 😞
I've noticed something weird... I tried to uninstall clock updates, in case the bug is in the latest version of the clock app. However after uninstalling the updates, the app seems to be on the latest version (according to galaxy store).
What version of the Clock app do you have ? I have 12.0.05.7 (after uninstalling)
Also since I uninstalled clock updates, all my tests seems to be working. We'll see when the real life scenario comes how it will behave...
OK, I did a bit more testing...
I noticed the following:
When the alarm rings, it uses the sound level of the notifications volume. So, regardless of whether you have do-not-disturb or not, if the notification volume is zero, there is no sound when the alarm rings (see pic)
Now, if you have the 'Vibrate' or 'Mute' sound mode, the level of the notifications volume automatically goes to zero. The only way to have volume other than zero is to have 'Sound' mode (see pic)
I'm pretty sure that in the past when I had it in 'Vibrate' it didn't change the volumes, it just didn't rang.
I usually have my phone on 'Vibrate', so the alarm doesn't ring... 😞
Also I have various Bixby routines which changes the notifications level during night, before bed, etc, so again no alarm... 😞
I need to change my settings and routines to actually have my phone on 'Sound' mode in order for the alarm to ring.
Hope it helps this time.