Why is there no sound on my calendar when alerts?

[iMore Question]

When I set an appointment on my calendar and set the reminders to notify me in advance, I get no sound to remind me of the appointment. I have set an alert an hour before and a second alert 15 min before.

 

[Just_Me_D]

Did you select an alert tone?
Is the Do Not Disturb feature enabled?
Is the device muted?
Is the volume level too low?