About
On an Apple device, such as an iPad or an iPod Touch, notifications will not produce a sound if they are generated when the application is “running”
Solution
A notification sound will not be generated and notifications will appear as pop-up messages
IF:
The mobile application is open (You can see the application)
A notification sound will be generated and notifications will display according to the method selected in the device Settings --> Notifications --> Notification Center --> Teletracking
IF:
Another application is running
or
The display is "sleeping"
or
No applications are running (you are on the main screen where you see only icons)
Symptoms
Notification sounds not generating on mobile