Symptoms
When a new email message is received, or when a calendar reminder notification pops up in Outlook Web App, sound alerts do not work in a Microsoft Exchange Server 2013 environment.
Cause
This issue occurs because the extension type for .mp3 files is not set.
Resolution
To resolve this issue, install Cumulative Update 7 for Exchange Server 2013.
Status
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
