By default, Windows Server 2012 has disabled audio because probably most servers won’t need it. Below will help you to enable audio in Windows Server 2012.
Open the Start screen, click Administrative Tools and open the Services shortcut. Next, double click the Windows Audio service and set its Startup type to Automatic. Repeat this process for the Windows Audio Endpoint Builder service. If you want to use audio immediately, also click the Start button in the Properties window of both services in addition to changing the Startup type.