Alarm not working correctly on iPhone after iOS update

If your alarm didn't go off as expected and you found your phone displaying a "snoozing" message when you looked at it, it's possible that the alarm was accidentally snoozed or silenced

1. Restart your phone: Restarting your phone can sometimes help fix software issues that may be preventing your alarm from going off.
2. Test your alarm: Set a test alarm for a few minutes in the future and make sure that it goes off as expected.

If the alarm volume is too low or quiet

Do Not Disturb and the Ring/Silent switch don't affect the alarm sound. If you set your Ring/Silent switch to Silent or turn on Do Not Disturb, the alarm still sounds.

If you have an alarm that doesn't sound or is too quiet, or if your iPhone only vibrates, check the following:

• Set the volume on your iPhone. If your alarm volume is too low or too loud, press the volume up or volume down button to adjust it. You can also go to Settings > Sounds & Haptics and drag the slider under Ringtone and Alert Volume.
• If your alarm only vibrates, make sure that your alarm sound isn't set to None. Open the Clock app, tap the Alarm tab, then tap Edit. Tap the alarm, then tap Sound and choose a Sound.
• If you connect headphones to your iPhone, the alarm plays at a set volume through the built-in speakers on your iPhone as well as wired and wireless headphones.