Alarm is silent

Greetings augustine292,

Thanks for visiting the Apple Support Communities! It seems the alarm on your iPhone is silent.

Is the behavior due to Attention Aware features being enabled? When this setting is enabled, alarms and notifications will go silent when looking at your iPhone:

About Attention Aware features on your iPhone X or iPad Pro - Apple Support

If unrelated to Attention Aware features, then check out the information in the article below:

How to set and manage alarms on your iPhone - Apple Support

"Get help with alarms

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 button up or down to adjust it. You can also go to Settings > Sounds & Haptics and drag the slider under Ringers And Alerts.
• 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 use iOS 11 or later and you connect headphones or speakers to your iPhone, the alarm plays at a set volume through the built-in speakers on your iPhone as well as wired headphones and speakers. It doesn't play through wireless headphones and speakers."

Kind regards.

I kind of had the same problem. I would set multiple alarms to wake up late. To find alarm is going off but no sound is coming out. What I have learned by trial and error. Is if you go into settings click on face ID and passcode. Scroll down to attention awareness features. And turn it off. That has seemed to fix my issue. I think what was happening is the iPhone would think that I looked at it when the alarm first went off. Hope that helps.