- Make sure Settings > Do Not Disturb is not activated
- Make sure you have most recent iOS version installed
- Make sure Settings > Notifications > Calendar > Allow Notifications is activated
- Make sure Settings > Notifications > Week Cal > Allow Notifications is activated
- Check the volume on the ringer
- Go to Settings > Sounds and check to see whether “Ringer and Alerts” is muted. If it is muted, make sure you slide the volume up
- Check the mute button. Your iPhone might frozen in mute mode. Flick the Mute button on and off several times
- Disable notifications for Calendar in Settings > Notifications
Turn off your phone and turn Settings > Notifications > Calendar back on - Restart your device by pressing and holding the sleep/wake button until you see the slider then slide the slider
- Reset your device by holding down the home button and the power button (wake/sleep) until you see the Apple logo
- Reset network Settings. Go to Settings -> General -Reset -> Reset Network Settings
Reset All settings
Hold the home and lock button together for few seconds until the iPhone restarts itself
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