How to fix iPhone 16 Pro Max not receiving phone call and alarm sound notifications?

Check your iPhone settings

Go to Settings and turn on Airplane Mode, wait five seconds, then turn it off. Check Do Not Disturb. Go to Settings > Focus > Do Not Disturb and make sure it's turned off. Check for any blocked phone numbers.

If you can't make or receive calls on your iPhone - Apple Support

If the alarm volume is too low or quiet

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

If your alarm 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 Alerts.
• If your alarm only vibrates, make sure your alarm sound isn't set to None. Open the Clock app, tap the Alarms tab, then tap Edit. Tap the alarm, then tap Sound and choose a Sound.
• If you connect headphones to your iPhone, the alarm will play at a set volume through the built-in speakers on your iPhone as well as wired and wireless headphones.
• When you use StandBy, haptics for your alarms are disabled. To make sure that your alarm sound isn't set to None: open the Clock app, tap the Alarms tab, then tap Edit. Tap the alarm, then tap Sound and choose a Sound.

Manually adjusting the time on your iPhone in Settings to change app behaviour, like game timers, isn't recommended and can affect alarms.

How to set and change alarms on your iPhone - Apple Support (IN)