My calendar alerts quit sounding.

[renasiphone6plus]

My calendar alerts quit sounding. When my phone is locked, the moon / do not disturb sign is on. I've tried to change it! But I'm unable to click it off! What do I do? By the way, all the other ringers work when it's locked! Just the calendar sounds have quit.

 

[Ledsteplin]

First do a hard reset.
7 Reset
Hold the power/wake button and the volume down button at the same time until the Apple logo appears. Then release.
Older phones:
Hold the top or side power/sleep button and the home button at the same time until the Apple logo appears, then release.

Then go to settings > Do Not Disturb > turn manual off> set schedule as desired, or leave off.
If that doesn't work, try Reset All Settings.

Go to Settings >General >Reset >Reset All Settings. This resets to default everything in Settings, including notifications, alerts, brightness, and clock settings like wake up alarms.