I once had a problem with a new Xiaomi phone where the OS would put the clock app to sleep and the prevent it’s background activity, missed 3 alarms before figuring it out.
I had the same issue, but i was using a third party app because i don’t really like the default one and a year later the problem started, now i am forced to use the default app if i don’t wanna my boss waking me up again
You can disable the optimisations for specific apps, should be under battery settings. At least that did it for me.
I did the day i installed the app, i really don’t know why it stopped working
Never an issue for me
Ive had this issue on multiple iphones and android phones its contributed a lot to my lack of trust in electronics
Could be internal damage. At least, that was the case with my old phone.
Samsung timer app has alarms fine, but the timers have no sound
I’ve had a similar issue on android, where the alarm is late. Shortest, but still late, was 3 minutes, and longest was for over an hour.
Are you using an alarm that tries to track your sleep?
Nope, standard alarm with the default clock app on my phone.
Your device is faulty. If it’s new enough, seek a fix via warranty.